"And who'd have guessed they'd come together on their own?"
The princess to be rescued, or the Prince Charming to sweep the heroine off her feet. Or just someone that happens to become romantically involved.
It's a Super Trope so universal, that there are too many specific examples to list. There are a few in the list below.
Compare Attraction Tropes, Flirting and Courtship, Dating Tropes, Marriage Tropes, Contrasts Asexual and Celibate Hero, who are immune to this.
More innocent Sister Trope to Lust Object.
Sub Tropes:
- The Ace
- Action Girlfriend
- Adorkable
- Amazon Chaser
- Badass Gay, usually for the Gay Aesop
- Bastard Boyfriend
- Bastard Girlfriend
- Beast and Beauty
- Bespectacled Bastard Boyfriend
- Betty and Veronica
- Betty and Veronica Switch
- Big Bad Friend, when they pull a Heel–Face Turn because of The Power of Love.
- Bokukko
- Broken Bird
- Cat Girl
- The Charmer
- The Chick
- Clingy Jealous Girl
- College Widow
- Cowboy Cop
- Crazy Jealous Guy
- Cute Sports Club Manager
- Damsel in Distress
- The Dark Chick, when they pull a High-Heel–Face Turn.
- Dark Mistress
- Dating Catwoman
- Deconfirmed Bachelor
- Defrosting Ice Queen
- Demoted to Satellite Love Interest
- Determined Widow
- Divine Date
- Disposable Fiancé
- Disabled Love Interest
- Disposable Love Interest
- Distressed Dude
- Dogged Nice Guy — because Single Woman Seeks Good Man
- Dominatrix
- Dungeonmaster's Girlfriend
- Eerie Pale-Skinned Brunette
- Femme Fatale
- First Girl Wins
- Girl Next Door
- Girl of My Dreams
- Girl of the Week
- Green-Skinned Space Babe
- Hair of Gold, Heart of Gold
- Hello, Nurse!
- The Hero
- Heroes Want Redheads
- Hooker with a Heart of Gold
- Hospital Hottie
- Hot Librarian
- Hot Scientist
- Hot Scoop
- Hot Teacher
- Implied Love Interest
- Incompatible Orientation
- Incorruptible Pure Pureness, since Single Woman Seeks Good Man
- Innocent Fanservice Girl
- Insecure Love Interest
- Jerk with a Heart of Gold
- Jungle Princess
- Knight in Shining Armor
- Knight in Sour Armor
- Lady of War
- Ladykiller in Love
- Last Girl Wins
- Likes Older Men
- Likes Older Women
- Little Sister Heroine
- Lonely Rich Kid
- The Lost Lenore
- Love-Interest Traitor
- Loves My Alter Ego
- Mad Scientist's Beautiful Daughter
- Magical Girlfriend
- Magnetic Girlfriend
- Manic Pixie Dream Girl
- Master of the Mixed Message
- Meganekko
- Morality Pet
- Muggle-and-Magical Love Triangle
- Mr. Fanservice
- Ms. Fanservice
- Naughty Nun
- Nice Guy
- Non-Action Guy
- The Not-Love Interest
- New Old Flame
- The Obstructive Love Interest
- Official Couple
- Old Flame
- Old Flame Fizzle
- The One That Got Away
- Peerless Love Interest
- Prince Charming
- Prince Charming Wannabe
- Princely Young Man
- Proper Lady
- Rebellious Princess
- Reformed Rakes
- Relationship Revolving Door
- Relationship Sue
- Replacement Love Interest
- Rich Bitch, since All Guys Want Cheerleaders
- Robot Girl
- Romantic False Lead
- Romantic Runner-Up
- Romantic Vampire Boy
- Sage Love Interest
- Satellite Love Interest
- Second Love
- Seemingly Wholesome '50s Girl
- Self-Proclaimed Love Interest
- Settled for Gay
- Shrinking Violet
- Significant Green-Eyed Redhead
- Sleuth Dates Cop
- Southern Belle
- Speech-Impeded Love Interest
- Spirited Young Lady
- Spoiled Sweet
- Stacy's Mom
- Stalker with a Crush
- Sugar and Ice Personality
- Tall, Dark and Snarky
- The Tease
- Temporary Love Interest
- Third-Option Love Interest
- Trickster Girlfriend
- Troubled, but Cute, since All Girls Want Bad Boys
- Tsundere
- Understanding Boyfriend
- Unwanted Harem
- Unwanted Spouse
- Useless Boyfriend
- Well, Excuse Me, Princess!
- Wet Blanket Wife
- Widow Woman
- White Magician Girl
- Woobie, Destroyer of Worlds, since they're Troubled, but Cute
- Yamato Nadeshiko
- Yandere
