Gone With the Wind
When wealthy Southern belle Scarlett O'Hara (Vivien Leigh) learns that Ashley Wilkes (Leslie Howard), whom she's secretly in love with, is engaged to Melanie Hamilton (Olivia de Havilland), she decides to tell him at a party about her feelings for him. However, Ashley is not swayed, and responds that he's much more suited to Melanie.
Rhett Butler (Clark Gable), who has overheard their conversation, promises to Scarlett that he'll keep her secret. The party is interrupted when it's announced that the Civil War has begun. As the men leave to enlist, Melanie's younger brother Charles asks for Scarlett's hand in marriage. She agrees, even though she doesn't love him.
She's quickly widowed, and still in love with Ashley, she waits for his return. Meanwhile, Rhett professes his feelings for Scarlett, and insists he will win her over.