Murtogg: If he were telling the truth, he wouldn't have told us.
Captain Jack Sparrow: Unless, of course, he knew you wouldn't believe the truth even if he told it to you.
A Stock Phrase. Alice has just done something/been somewhere/went on a crazy adventure, and Bob asks her about it, usually with "Where Were You?" Rather than boring the audience with the story, or using a quick Fade Out-Fade In to skip it, Alice simply says "You Wouldn't Believe Me If I Told You..."
And It's a Long Story, anyway...
A common variation (or addition) is: "I wouldn't believe it myself if I hadn't seen/lived/heard/witnessed/experienced it." And as the examples show, there are several permutations of this sentiment. In short, it's the way a character avoids the Cassandra Truth situation, or at least tries to—the questioner may insist on hearing the story anyway, often by saying "Try me."
The opposite is Cassandra Truth, where Alice does tell Bob, and Bob doesn't buy it. Likewise, contrast to You Have to Believe Me!, where someone tells the truth while making it sound as crazy as possible. Related is Sarcastic Confession, where Alice tells Bob in a sarcastic manner to prevent him from taking it seriously. Contrast Suspiciously Specific Denial.
- While never actually said in Code Geass, this trope is the likely reason why Lelouch never explains to Suzaku that his Geassing of Euphemia was an accident.
- A major plot of G Gundam is that Kyoji made a clone of himself with all of his knowledge and skills in order to protect his brother Domon as he was currently under the control of the Dark Gundam and incapable of helping Domon himself. When asked by Domon why he didn't reveal this secret earlier, Kyoji's clone states, "You were so hot-headed back then, Domon; you wouldn't have believed me if I had told you."
- In Digimon Tamers, the Tamers would try to keep the Digimon secret from their parents as they wouldn't believe them.
- In Puella Magi Madoka Magica, this is the reason Homura gives as to why she never told anyone about the terrible secrets behind Magical Girls. And she knows this for a fact: in previous timelines, she did try telling her friends, but they never believed her.
- In Durarara!! it is employed by Izaya to mess with Earthworm after she kidnaps and 'tortures' him. He has Haruna control Earthworm's allies to free him and to incapacitate them once his people storm the place. He taunts Earthworm as her plans fall apart by answering her questions with "You wouldn't understand".
- In Kyon: Big Damn Hero, after Rika Fuurude convinces Kyon, her nephew, to trust her and tell her his story about the supernatural by her telling him her own supernatural experiences he explains that his adventures, while true, are still difficult to believe.
Kyon: (through Manly Tears) I...it's... It's nothing nearly that bad. I wouldn't... You may still think I'm crazy, and... Well, parts of this are secrets I don't really tell anyone else, but...
- In Insomnia, Link acts on this trope's principle whenever he shrugs off Tatl's attempts of uncovering his backstory.
- In Intercom, Riley uses this to avoid telling her parents about being able to hear her emotions' voices.
- Sinbad: Legend of the Seven Seas: After Sinbad's encounter with Eris (while in an air bubble underwater), his crew scoop him up back up and onto the ship.
Kale: What happened down there?
Sinbad: You wouldn't believe me if I told you.
Kale: Try me.
Sinbad: All right, here goes. So I meet Eris, the Goddess of Chaos. She's got a major crush on me, and she invited me back to her place.
Kale: Ha! That's a good one! Goddess of Chaos? Oh, I'm writing that down.
- IMDb Search Quotes for "You wouldn't believe me if I told you". The phrase (or a reasonable variation thereof) appears in (among others):
- Played with in The Lion, the Witch, and the Wardrobe when the Professor finds the kids just as they return through the wardrobe from Narnia after spending years there. When they give his stock line, the Professor (who went to Narnia himself as a boy) playfully responds, "Try me."
- The Final Countdown uses the, "They're never going to believe it," variation as the USS Nimitz is returning to Pearl Harbor, having just spent about a week in 1941 thanks to Time Travel.
- In SpaceCamp, this is essentially how Zach Bergstrom wants to deal with the errant launch of Atlantis.
Brennan: How am I supposed to keep a lid on this? People for 500 miles know the shuttle went up!
Zach: Tell'em the truth: we launched my wife and five kids from the SpaceCamp. They'll never believe it.
- In The Wizard of Oz when Glinda tells Dorothy at the end that the ruby slippers can take her home, Dorothy asks why Glinda didn't tell her at the beginning, and Glinda says "You wouldn't have believed me." This is actually a patch for an Adaptation-Induced Plot Hole. In the book, the Good Witches are two different people, and the Witch of the North actually didn't know the slippers could get Dorothy home, while Glinda was the Witch of the South, who did know.
- There's a joke about an elephant that runs away from the circus and ends up in the garden of an old woman who's never seen an elephant in her life. She, naturally, calls the police.
Old woman: ...and he's pulling out my carrots with his tail!Cop: "...carrots with tail." Rrrright. What does he do with them after he's pulled them out?Old woman: ...Officer, if I told you, you wouldn't believe me!
- A variation: In The Bible, Luke 22, the arrested Jesus is interrogated and asked to confirm that he claims to be the Christ. He answers with pretty much this phrase. If Our Lord being a Deadpan Snarker distresses you, wait 'til you find the puns.
- A slight variation is said by Shay Bourne to Father Michael in Jodi Picoult's Change of Heart:
They moved to the far side of the room, and I leaned closer to Shay."Are you okay?""You wouldn't believe it if I told you.""Oh, try me."
- Happens in The Dresden Files novel Changes, where the Good Cop is questioning Harry about a building that was bombed. Harry delivers this line when asked if he knows who did it, then the two change subject and talk a while before the cop decides he's innocent and lets him go. Before Harry leaves, the cop asks who really did it, to which he responds "Vampires," adding "I told you you wouldn't believe me" a minute later when the cop goes through surprise and disbelief.
- Note that said cop was a Living Lie Detector, so he realizes Harry actually believes his answer is the truth.
- In The Gatekeeper: The Gate Contracts, George Green has to explain to his boss what happened with Lynn in the Men's restroom:
Dr. Sign: Okay George, let's hear it.
George: Lynn and I went to the cafeteria to eat. I told her to wait a minute, I had to use the bathroom. I went in and used the urinal as someone else came into the bathroom. When I turned around I discovered that she was the someone else. She proceeded to make various cooing sounds and I attempted to tell her this was inappropriate. She unzipped my fly, removed my penis from my pants and got on her knees. I put my hands on her shoulders in an attempt to push her away. At that moment the [campus police] officer came into the bathroom." I smiled a little. "I'm sorry, Dr. Sign, I shouldn't be smiling about this. I know this is serious, but I got a mental picture in my head of what he saw and trying to explain to him it wasn't what he thought it was. I looked at what was happening. I said to the officer that I wasn't going to say a word to him, if I was him and I told him what I know, I wouldn't have believed it either.
- In WebMage, Ravirn is placed under a "Cassandra Curse" that prevents people from believing anything he says about the Big Bad. When Eris tries to question him about a related matter, he tells her that she wouldn't believe him if he told her — which she naturally doesn't believe.
- Used in Buffy's second season finale, after Spike has offered to help her prevent the apocalypse.
- Doctor Who:
- It's a common reply by the Doctor in regards to questions like "How did you get here?", "How do you know that?", "What makes you think our benevolent leader (who is actually the Master) is up to something bad?" and so on. The few times they do explain, people predictably don't believe them.
- At the end of "The Three Doctors", a man is zapped back to his small English village after being accidentally sucked into one of the show's typical plots. His wife appears and starts peppering him with questions about where he disappeared to. He listens stoically, then grunts "You'd never believe me, woman. Supper ready?" and stomps into his house.
- "Rise of the Cybermen" features this exchange, where Alternate Universe Pete Tyler wants to know how the Doctor knows so much about the Cybermen as they flee the Tyler mansion:
Pete: Who are you? How d'you know so much?
The Doctor: You wouldn't believe it in a million years!
- Subverted in "Death in Heaven". When Osgood asks who Missy is, the Doctor uses this line except Osgood's already guessed that she's the latest incarnation of The Master. "That was fairly quick."
- Early Edition had this fairly often too, when Gary Hobson, a man who gets tomorrow's newspaper today, is asked how he knows that things are going to happen before they do.
- Eerie, Indiana: In "The Broken Record", Marshall's response when his mother asks him to tell her something that isn't scary.
- In an episode of Full House, Jesse receives some timely advice from a man who looks like (and is hinted that he might be) Elvis Presley, and when Jesse mentions that he looks familiar, the stranger says people mistake him for Wayne Newton. When Jesse is telling everyone else about the stranger, he realizes that being a huge Elvis fan, it was just too weird that he got advice from a man who looked like Elvis, so he said the man looked like Wayne Newton.
- Used by Richard in the Lost episode "Dr. Linus"; like the Professor above, Jack responds "Try me," as a) he has been through an awful lot of weird shit, and b) he is getting a bit sick of people dodging questions.
- In Pushing Daisies, Chuck tells Ned that Olive wouldn't believe that Ned had brought Chuck back to life even if she told her. Ned asks her how she knows that, and she says, "because I told her and she wouldn't believe me."
- Sliders had this nearly every episode, when they had to convince people in whatever Alternate Universe they were visiting of where they came from.
- So Random!: Rufus's Catchphrase is "Oh, you're not going to believe this." Naturally, every word he says is true, no matter how ridiculous.
- At the end of Conker's Bad Fur Day (And the remake.) Conker says this exact line to the bartender when asked "Ya look horrible! what happened to you?" Before being poured a glass of scotch and asking for the whole bottle.
- The player can invoke this in Mission Critical after waking up with the first officer of the USS Lexington angry, holding a sidearm on them, and demanding answers. It goes about as well as one would expect.
- Player: You won't believe a word.Tran: Try me.*Tell her everything that's happened, including the traitor aboard the ship, the UNS ambush and resulting death of everyone else on board both ships, the destruction of the alien ruins on the planet, the resulting loss of the war, Time Travel, the end of all known space due to a later Robot War (started by the humans), and the sentient AIs who sent you back to prevent it.*Tran: That is the most ridiculous story I've heard since I graduated from the naval academy.
- Which raises the question, what the hell story did they tell her back in naval academy?
- At the beginning of the Warden's Keep DLC for Dragon Age: Origins, you can ask Levi Dryden how he was able to pick his way through a series of mountain tunnels to Solider's Peak. He utters this phrase in response, but when you press him, he reveals that it came to him in a dream. It turns out to be true; that was how the mage Avernus reached out to Levi, encouraging him to search the (not entirely) abandoned fortress.
- In King's Quest V: Absence Makes the Heart Go Yonder!, Graham gets carried away by a giant Roc and is only barely rescued from being eaten by its young by a friendly eagle, who deposits him on a beach. When Cedric asks where Graham went, he responds with the trope name.
- During the final level of Crysis, Nomad finally meets with Psycho again, who had been supporting him throughout the game up until they were separated, and sees that he has secured an alien life-form for the U.S Navy to study. Nomad asks Psycho how he got the alien off the island and onto a Naval vessel, and Psycho responds saying, "Long story. You wouldn't believe me if I told you." However there was a DLC for the original PC version where we do in fact see how Psycho got it.
- In Persona 4, this trope is the reason why the Investigation Team (a ragtag group of high school kids) can't turn to the police for help. Which is proven true late in the game when the Protagonist gets hauled off to Police Station by Dojima (his uncle and a detective) after receiving a threat letter in the mail.
- In Zero Time Dilemma, Carlos used "SHIFT" to send his consciousness between different versions of his body in different timelines, and ends up in the timeline where he killed Akane (in self-defense, following a misunderstanding over Junpei's murder). When Eric brings up that they all know he killed Akane, Carlos tries to explain that even though that might be the case it "isn't what he did right now". He responds with "I doubt you would believe me if I tried explaining it", when Eric asks what he's babbling about. He does try telling them, to which both Sigma and Diana understand straight away due to having the same SHIFT ability. Whereas Eric continues to think the three of them are sprouting crap.
- At the end of Chapter 3 of The Longest Journey April meets her friends in her room. They ask her what she was taking her time, for which this is her answer. After finally telling them that she was visiting a fantasy world and she was chosen to save both worlds from Chaos, Charlie says that he believes her because he knows she wouldn't lie.
- In the Justice League Unlimited episode "Double Date", Green Arrow asks The Question why he's helping Huntress track down the man who killed her parents. Question responds with this, and everyone just assumes he says it because his motives are something insane. (It turns out he's just trying to impress Huntress.)
- In The Legend of Korra, Bumi, known for his tall tales, delivers this line almost word for word after single-handedly destroying an entire Water Tribe encampment with little more than a flute and pure guile.
- In the Looney Tunes short Tweet and Sour, Sylvester is threatened with being sent to the violin string factory if he's caught trying to eat Tweety again. After spending the rest of the cartoon trying to save Tweety from another cat, Granny walks in just as Sylvester was putting him back in his cage. The cat stammers trying to explain, but he then gives up, saying "What's the use? She'll never believe me."
- One sketch on Robot Chicken features pee building up outside of a plane, and freezing in the cold air. It keeps building up and getting bigger until it forms a giant frozen piss-ball and breaks off, plummeting to Earth and ultimately crushing the British royal family. The headline simply read, "You're Not Going To Fucking Believe This!"
- Scooby-Doo! and the Goblin King. At the end of the episode, the benevolent Goblin King casts a spell that erases memory of the night's events from everyone but Shaggy and Scooby. When the rest of the gang asks what happened, they use the trope.
- In the Grand Finale of Spider-Man: The Animated Series, Madame Web assembles a team of Spider-Man from different parallel worlds. One of them, however, admits that he doesn't actually have Peter's life or his powers. When asked who he is, he gives this reply. Near the very end, it turns out he's an actor from a world where Spidey is a fictional character.
- Star Wars: The Clone Wars: At the end of "Ghosts of Mortis", Anakin says this to Rex after the Jedi's ship is mysteriously returned to realspace a few seconds after they disappeared, at the end of a visit to an Eldritch Location.
- Star Wars Rebels: In "Zero Hour", Kanan says this by way of explanation for why he never told Hera, or anyone else except Ezra, about the Bendu, a mysterious and extremely powerful Force-wielder who lives on Atollon.
- Teenage Mutant Ninja Turtles (2003): In "Attack of the Mousers", Master Splinter is (understandably) afraid that April O'Neil will tell people about the existence of himself and his four sons, but April points out that even if she did tell anyone, they probably wouldn't believe her—even Leo and Mikey agree that April does have a point.