Come the night she was such a pleaser
Mary Hill was such a thrill after dark
In Cherry Hill Park!"
She seems to be the perfect, wholesome teenage girl of The '50s. By day, she's a sweet, innocent ultra-virgin who dresses in knee-length skirts and tasteful sweaters, and repeatedly says things like "that's swell!" and "peachy keen!". She might wear glasses, attend Catholic school, or even be a Preacher's Kid. Her parents and teachers talk about what a "good girl" she is, but all the kids at school (except for the "squares", of course) know about her "reputation". By night, she drinks, smokes, and hangs out with (gasp!) boys. She "parks" with them, while the car radio plays Nothing but Hits, and may even have experienced sexual intercourse. (And if she is still a virgin, she may only be one in the technical sense.) In other words, she's either something of a Hot Hypocrite or at the very least something rather different from what she appears to be. After all, she doesn't want to be a "square" and the male hero needs a girlfriend that appears respectable but isn't a prude. Bonus points if her mother or grandmother was a flapper, teaching their daughters and granddaughters the way of sly rebellion and liberation.
She could be seen as a subversion of the ultra wholesomeness stereotypically associated with the Fifties, but it's more likely just an example of Truth in Television (more or less). There were large differences in premarital sex rates after the pill was introduced in 1961, and again from the sexual revolution. Despite this, by the 1970s, the '50s were often just treated as the present in regard to sexual behavior, except with far more hypocrisy. Perhaps it's just the fact that the whole franchise of Fifties nostalgia films about the sex lives of teens couldn't possibly exist without her. She is a perfect combination of the nostalgic '50s charm and 1970s priorities. It is no coincidence when this trope became popular. And, of course, this type of ersatz "good girl" can still be found (or suspected) in more culturally or religiously conservative environments even in the present day.
A variant of Naughty by Night, and Sub-Trope of Living a Double Life. See Hot Librarian for her more adult (and less intentionally sexy) counterpart. Contrast with the sexy-on-the-outside, innocent-on-the-inside Hooker with a Heart of Gold.
- Kathryn Merteuil in Cruel Intentions definitely qualifies. Though at the end of the movie, her game is exposed for all to see, courtesy of her deceased step-brother's diary.
- Pleasantville: Played with, where a girl from our day and age ends up stepping into this role... and by the time the movie's done, every girl in town is like that to some extent, except the girl who started the behavior.
- Marty's mother Lorraine in Back to the Future wants to be this, to Marty's understandable alarm. Not only is she Marty's mother, but she hypocritically also berates her children for acting this way in the future (at least until Marty improves history).
- Janet Weiss from The Rocky Horror Picture Show. She's an innocent girl who is Brad's fiancee. Though, during her time in the castle, she has sex with both Frank N. Furter and Rocky...the latter prompting pure jealous rage from the former (over him sleeping with her, not vice versa). In the end, she's confused about what has occurred, but also realizes the benefits of living a sexually active life.
- Mary Lane of Reefer Madness, the ingenue of ingenues, takes one puff of "marijewana," at which point... Some things just need to be seen.
- The plot of Hairspray starts when one of the seemingly wholesome girls on the in-universe The Corny Collins Show has to take a leave of absence from the show...for nine months.
- Played for Laughs in Not Another Teen Movie, where a bit character who fits the bill also suffers from Hollywood Tourette's.
- Subverted in the pilot of Happy Days where one girl's "reputation" turned out to have originated entirely from boys bragging about how far they'd gotten with her.
- Professional Wrestling actually brought us one of these in the form of Cherry, a manager for Deuce & Domino, a tag team of greasers. Unfortunately for Kara Drew, the girl behind the gimmick, it was her only shot at the big time. According to some sources, she was reportedly released for being "too fat" to be a Diva.
- Twin Peaks, with its very retro-'50s aesthetic, naturally played with this one. Given that essentially every character on the show had a secret of some kind, every female character was at least a borderline example of this trope, but a few really stand out.
- Laura Palmer, the murdered homecoming queen, is gradually revealed to be one of these - a cokehead with several secret boyfriends, many of them much older than her. It's hard to be too judgmental, given that she was the victim of repeated sexual abuse by her demonically-possessed father.
- Audrey Horne, cigarette-smoking daughter of the town millionaire, is initially set up as the Wolf in Sheep's Clothing version of this, but gradually becomes more of a Good Bad Girl through her investigation of Laura's murder and her crush on Agent Cooper.
- Donna Hayward, by contrast, is initially set up as the Betty to Audrey's Veronica, the conscientious good girl and best friend to Laura. As the series progresses, her attempts at being an Amateur Sleuth and finding Laura's killer become increasingly reprehensible, as unlike Audrey, Donna puts other people in danger, and even accidentally drives a man to suicide, and she uncovers no real information.
- Morello in Orange Is the New Black, whose "entire world view is based on West Side Story," making her a bit of a 1950s girl in the 21st century. She seems very sweet and very devoted to her fiance, but it turns out she's actually kind of racist. And she's having a lesbian affair. However, her naivete might be genuine, as it turns out her fiance doesn't visit and she's the only one who still thinks he's waiting for her. In season 2 it's revealed that her "fiance" was actually a guy she was stalking, and she was arrested for putting a car bomb under his actual fiancee's car.
- Cindy on Good Girls Revolt is a Seemingly Wholesome Sixties (Later Seventies) Girl who dresses cutely, is married, shy, and sweet. Shes also an alcoholic and cheating on her husband, all the while being one of the main actors in the womens plan to file their complaint.
- The Riverdale take on the Archie Comics character Betty Cooper fits this trope, the show having a strong '50s Retro Universe aesthetic much like Twin Peaks (one of its main inspirations). While Betty's demeanor, style of clothing, and iconic ponytail definitely seem wholesome as can be, she self-admittedly has a "dark side", which may or may not have something to do with whatever mental condition she has that makes her dependent on Adderall. When she leashes out as "Dark Betty", she expresses a lot of anger and a certain degree of sexual repression.
- Chuck Berry's hit "Sweet Little Sixteen" narrates a girl like this.
Sweet little sixteen
She's got the grown-up blues
Tight dresses and lipstick
She's sportin' high heel shoes
Oh, but tomorrow morning
She'll have to change her trend
And be sweet sixteen
And back in class again.
- "A Sweet Old Fashioned Girl" by Teresa Brewer tells both sides of the story in first-person. It was a top ten hit on both sides of the Atlantic in 1956, suggesting the record-buying public at the time found the dichotomy just as amusing as we do today.
- Then there was the aforementioned Mary Hill in Billy Joe Royal's "Cherry Hill Park"note It's a fantastically catchy '60s pop tune that deals with something potentially salacious.
- The girls in the Garfunkel and Oates song "The Loophole" are a modern example.
- Gender inverted with Cry Baby's brother from the self-titled Melanie Martinez Concept Album. He looks like an average, studious young man but is a drug user with implied negative (or at least depressive) character traits. The entire family keeps up a facade of happiness but Cry Baby herself is a Broken Bird. She cracks over the album.
- Streetheart has "Snow White" mentioning that she has the perfect disguise.