Angel, Season 1

[An offer of help from a wealthy admirer has moved Cordelia to tears.]

Cordelia:
Oh, God, I'm sorry! I'm getting all weepy in front of you. I probably look really scary. I finally get invited to a nice place... with no mirrors, and... lots of curtains... Hey! You're a vampire!

Russell Winters:
What? No, I'm not.

Cordelia:
Are too!

Russell:
I don't know what you're talking about.

Cordelia:
I'm from Sunnydale - we had our own Hellmouth! I think I know a vampire when I... am... alone with him... in his fortress-like home. And, you know? I think I'm just feeling a little light-headed from hunger. I'm just wacky! And kidding!! Ha, ha!...

Russell:
Truth is, I'm glad you know. It means we can skip the formalities.