Season 2 Episode 18: "Wrapped Up in Death"
Castle: Do you believe people get what they deserve?
Beckett: Well, if they do then I must have done something terrible to be punished with you.
Castle: Funny.
Agent Shaw: He cares about you, Kate. You may not see it. You may not be ready to. But he does.
Beckett: Yeah, well, the situation with Castle is... complicated.
Season 2 Episode 15: "The Mistress Always Spanks Twice"
Castle:You should really moonlight, trust me you would make a fortune. Come on isn't there anything you would like to do with your handcuffs besides arresting criminals?
Beckett:No.... but there is one hot wild kinky thing that I do like doing... Putting killers behind bars.
Castle:see your already a tease your halfway there.
Season 2 Episode 13: "The Third Man"
Beckett: You're such a metrosexual.
Castle: Yeah, well, better than being a pin-up boy.
Beckett: So you heard? And it's man, Castle. Pin-up man.