That's what's really exciting.
5 seconds sound clip from the The Seven Year Itch (1952) movie soundboard.
You can hear this line at 01:38:10 in the Blu-ray version of the movie.
Quote context
[...]
- How do you know what a pretty girl wants?
- I don't really know, but I imagine...
- You and your imagination. You think every girl's a dope.
- And from this, she's supposed to fall flat on her face. Well, she doesn't fall on her face.
- That's what's really exciting.
- If I were your wife, I'd be very jealous of you. I'd be very, very jealous.
- I think you're just elegant.
- The doorbell. Go ahead. I'll put the cinnamon on the toast.
- Morning, Dickie boy! Morning, morning, morning!
[...]