Three words, eight letters.

Chuck: Please don't leave with him.
Blair: Why? Give me a reason. And “I'm Chuck Bass” doesn't count.
Chuck: Because you don't want to.
Blair: Not good enough.
Chuck: Because I don't want to.
Blair: That's not enough!
Chuck: What else is there?
Blair: The true reason I should stay right where I am and not get in the car… Three words, eight letters. Say it and I'm yours.
Chuck: I ... I ...
Blair: Thank you, that's all I needed to hear.