But he was mean and he was coarse and unrefined
And now he's dear and so unsure
I wonder why I didn't see it there before."
So Alice and Bob don't know each other yet, or Alice regards Bob with either indifference or dislike. But then, she witnesses him committing — or becomes the recipient of — some single act of kindness (rescuing someone from bullies, stopping to help someone with errands, etc.) that makes her think "maybe he's not so bad after all." This causes her to develop a blossoming crush on him, or otherwise shoehorns the two towards a romantic relationship.
Psychology-wise, the trope works due to the belief on the part of the girl that only she has seen this "hidden side" of the guy, which makes her feel special and connected with him. After all, the appeal of the bad boy is that he only acts like a dick around people other than you. Savvy characters can exploit this.
Essentially, a form of Relationship Upgrade that tends to happen very early on in the Romance Arc, if not start it entirely. Rescue Romance, Rescue Introduction and Returning the Handkerchief are particularly common types of Samaritan Relationship Starter. A related trope is Single Woman Seeks Good Man, where one character is attracted to another because (s)he's usually like this.
- In Code Geass, Shirley thinks Lelouch is a cold, spoiled brat until she witnesses him helping out some strangers when no one else would, apparently a habit of his. And it wasn't just that he helped - it was that afterwards, he didn't boast or anything, he just went back to what he'd been doing as if nothing had happened. Thus begins her infamous and tragic crush on him.
- When they were children, Lelouch and Suzaku had this mutually. They had been fighting since they met, but one day, Nunnally went missing. Both of them wanted to find her, but they refused to work together - until Suzaku found her first, and Lelouch sees her laugh for the first time since their mother was killed, because of Suzaku. After that, they become friends (or more).
- Prior to the start of Horimiya, Hori only saw Miyamura as that gloomy looking long-haired guy in her class who kept to himself, always wore long sleeves, and was probably an otaku. Then he ended up helping her little brother when the latter was injured. Downplayed in that this simply led to the two of them becoming friends. The actual romance didn't come until later.
- When Shinji defeats the Angel in his first fight together with Asuka in Neon Genesis Evangelion.
- Even more so when he saves her from death by volcano by jumping into the lava without any sort of protective equipment.
- On the other hand, this eventually gets inverted: Asuka becomes allergic to anyone demonstrating kindness to her, deliberately mistaking their genuine intentions towards her as pity.
- Played for laughs in Ranma ˝ with Ukyo; she and Ranma already have an Arranged Marriage, but he's initially unaware and she's initially out for revenge because she thinks he abandoned her. When he interrupts her rant about being ruined for marriage and cursed to be alone forever by telling her that she's a very cute girl and will make someone a great wife someday, that's when she drops the vendetta and decides to give being engaged to him another shot. Especially because his other Arranged Marriage is a tsundere with whom he evidently does not get along.
- In Ratman, the Rebellious Princess character already kind of likes the hero, though she thinks of him as a wimpy kid who needs protection. Then she sees him rescue a kitten from being run over (without the benefit of superpowers) and she immediately upgrades her opinion to "has a hero's heart"—especially significant as the "real" professional heroes ignored the situation.
- It's also happen with Haruka, who begin to appreciate Taishi/ Fatman after seeing him calming down a child using his Transformation Sequence and free pizza on his own account. Taishi didn't know of this... and arranges a Rescue Romance situation to impress her. Hilarity Ensues. Then heartwarming ensues.
- In Midori Days, it's this trope, not Rescue Romance, that kickstarts Takako Ayase's crush towards Seiji Sawamura. Seiji does catch her attention after he rescues her from school delinquents, but she's still wary of him because she still believes he's a blood-thirsty fight seeker. It's only after witnessing Sawamura deliberately taking a beating without retaliating in order to save a friend and to defuse the hate the Delinquents have for him, that she falls in love with him.
- In Wild Rock, Yuni falls into an animal trap set by Selim. Selim gets him out and gently nurses him back to health. Since they're of rival clans, Yuni wouldn't have given him the time of day before this.
- Invoked in The World God Only Knows for the middle school girl's capture, which is mostly told from her perspective. Keima fakes being a member of the swim team and pretends to do really well and looks cool. When he disappears, she builds up a false impression of him as a really cool upperclassman (he calls it a free love potion to be a sempai), which balances against his bad reputation and has her develop a crush on him. And later when he's checking for goddesses, we see that unlike all of the other girls she does not even remember him because he managed to get out the runaway spirit while barely speaking to her. Which is a good thing.
- In Episode 13 of the second season of Death Note: The Abridged Series (kpts4tv), when Near reveals that Kira saved him from being molested the Foe Yay subtext becomes text-Near's still trying to catch Kira but their dialogue gets very flirty.
Light: So... you're a virgin?
- The My Little Pony: Friendship Is Magic fanfic Gimme Shelter suggests this trope is the reason that Fancypants and Fleur de Lis are seen together. Specifically, he took her in for the night after she got caught in a storm without her coat, and asked for a date in return, which she agreed to.
- In The Vow, Lord Shen and Lady Lianne start off on poor terms and for improvement to begin, it requires for her to openly defend him against slander said about his appearance and genetic health. This — along with the realization of how lonely she feels — makes him apologize for his behavior with an Apology Gift she can accept.
- In Dragon Age: Inquisition's Walking in Circles, Solas and Evelyn’s first interactions is her willing to be hit to keep his pendant safe. But it takes him to see her protecting an elven child and, once again, risking herself to keep him safe from his own mistake that he truly notices and develops affection for her, and much longer than that for him to actually see her as a true person with full emotional capability.
- Beauty and the Beast: When the Beast fights off wolves to save Belle, she takes a second look at him. The musical number "Something There," quoted at the top of the page, is a Falling-in-Love Montage in which Belle realizes this.
- Good Dick: The main character's relationship starts this way.
- The Hunchback of Notre Dame: Phoebus is attracted to Esmerelda from the get-go (as is basically every main character), but once he sees her stand up to Frollo and his guards to protect Quasimodo, it's definite. Esmerelda initially sees him as just another one of Frollo's mooks, but that changes for similar reasons.
- In Outlander, Freya reconsiders her opinion of Kainen after hearing how his valor in the fight against the bear saved her father's life.
- Deliciously played with in Red Eye, which sort of resembles a romantic comedy in the very beginning, before turning all creepy.
- Silver Linings Playbook: Tiffany is touched when she overhears Pat standing up for her in a conversation with one of her former coworkers.
- Zootopia: Nick and Judy are an intertwined example of this. Judy rescues Nick from a savage jaguar and then saves his life when they are both knocked off the Skytram platform which leads to Nick standing up to the Da Chief for her sake and then opens up to her about his childhood trauma. This leads to a deep friendship forming between them.
- Agnes Grey: While Agnes hears a lot of good things about Mr Weston (a new clergyman at her church), the first time she really meets him is just after he rescues an elderly widow's cat from getting shot by the local lord's gameskeeper. He stumbled upon said cat because he was on his way to visit said widow to read the bible to her to lift her spirits since she's been in poor health and worries about her immortal soul. This is, incidentally, when Agnes first starts developing feelings for him.
- This is what kickstarts the Will They or Won't They? for Barney and Robin in How I Met Your Mother, when Barney comforts Robin after she is dumped by a jerk boyfriend. They end up sleeping together, which leads to Barney realising he is in love with Robin.
- The Bible provides a variant: when Abraham's servant Eliezer is sent on a journey to find a wife for Isaac, he decides to pick the first woman who, when asked for a drink, offers to draw water for his camels as well. Given how physically exhausting it was to lug water out of a well for so many animals, the point was to pick a woman willing to go out of her way to help anyone in need.
- In the Neverwinter Nights mod The Aielund Saga, Criosa really starts to consider the male player character in this manner if you take the heroic dialogue options when helping out the dwarves at the start of chapter 3.
- A non-romantic example: in Dragon Age II, Hawke meets his/her lifelong best friend Varric when the dwarf apprehends a pickpocket who has stolen Hawke's money pouch. It's later clarified that Varric knew who Hawke was (thanks to their reputation) and had specifically intended to meet them, but the pickpocketing gave him an unusual way to introduce himself.
- Larisa's relationship with Landon in Sandra and Woo was kicked off when he helped her pass a math test.
- The Spectacular Spider-Man, Season 2: Jerk Jock Flash Thompson tries to hook up with quiet and artistic Sha Shan, completely failing to woo her when he relies on his usual sports reputation and personality to attract her attention. She only begins to respond to his affections when he reports to his coach that one of his teammates was using performance-enhancing drugs during their recent championship game (specifically Harry Osborn using Globulin Green, the drug that would turn Norman into the Green Goblin. His actions force the team to retroactively forfeit the game and lose their title, something that he had worked long and hard for (having even broken his leg for and costing him a potential scholarship), but he felt that the championship did not mean anything if had been earned dishonestly. After this, Sha begins to reciprocate his feelings.
- In Total Drama Island, Courtney finds out that Duncan is a Jerk with a Heart of Gold when she sees him tricking DJ with a replacement Bunny so DJ wouldn't be sad.