BARON ST. FONTANEL: A woman happily in love, she burns the soufflé. A woman unhappily in love, she forgets to turn on the oven.
Ah, those French barons; they are so clever! Women in love are fiery and consumed with passion; women unhappy in love are flat and listless. To make a perfect soufflé, you have to be just lukewarm in love, maybe. (Or, alternately, you could maybe just marry a super-rich prince and then hire someone else to make your soufflés.)
DAVID: Just one thing you overlooked. I haven't proposed and she hasn't accepted.
LINUS: Oh, don't worry. I proposed and Mr. Tyson accepted.
DAVID: Did you kiss him?
David is mad at Linus for controlling his love life in the interest of the family business. The kicker is that Linus wins; David does marry Elizabeth, even though he doesn't love her. The film presents Linus' affair with Mr. Tyson as ridiculous, but it's an affair that appears to win out. For a film so obsessed with love, it's awfully cavalier about poor David's fate.
LINUS: If you love her, take her. This is the 20th Century.
OLIVER: The 20th Century? I could pick a century out of a hat, blindfolded, and get a better one.
Sabrina is youth—but she's also the future. Putting social class before love is seen as hidebound and archaic. The modern thing is to let love conquer all—while traveling to the modern, chic city of Paris.
SABRINA: Certain songs bring back certain memories to me, too. Did you love her?
LINUS: I'd rather not talk about it.
SABRINA: I'm sorry.
LINUS: That's all right.
SABRINA: It's so strange to think of you being touched by a woman. I always thought you walked alone.
LINUS: No man walks alone from choice.
Is this Linus remembering the pain of a lost love? Or is it Linus lying through his teeth in an effort to present himself as romantic and attractive, so he can win Sabrina's heart and break up her relationship with David? You really can't tell. You're never entirely sure how much of a stinker Linus is, or when, or how much, love has changed him. That's part of the reason that the ending maybe has a little cloud over it. Will Linus really be good to Sabrina? Or is their love ultimately doomed because she's too trusting and he's a jerk?
LINUS: [slow dancing with Sabrina] How do you say in French my sister has a yellow pencil?
SABRINA: Ma soeur a un crayon jaune.
LINUS: How do you say my brother has a lovely girl?
SABRINA: Mon frère a une gentille petite amie.
LINUS: And how do you say I wish I were my brother?
Linus tries to seduce Sabrina of course in French, which is featured in the film as the language of love. Also, it's maybe best to be speaking a foreign language when you try to sneak your brother's girlfriend away from him. You want as few people to understand you as possible.