Nick: So where is this going?
Catherine: Ask me "What do you want from me Catherine?"
Nick: What the fuck do you want from Catherine?
Nick: How did you feel when I told you Johnny Boz had died, that day at the beach?
Catherine: I felt somebody had read my book and was playing a game.
Nick: But you didn't hurt.
Catherine: No.
Nick: Because you didn't love him.
Catherine: That's right.
Nick: Even though you were fucking him.
Catherine: You still get the pleasure. Didn't you ever fuck anybody else while you were married, Nick?
Beth Garner: Something's going on. You're sleeping with her, aren't you?
Nick: Why are you interested in her?
Beth Garner: My interest is in you, not her. She seduces and manipulates people. She'll do anything she can.
Nick: I thought you hardly knew her?
Beth Garner: I know the type. I'm a psychologist.
Nick: That means... you manipulate people too! You're a practicing psychologist. You're better at it than she is.
Nick: You wanna play hard, come on.
Nick: I'm working my ass off, I'm off the sauce, I even stopped smoking.
Beth Garner: How's not smoking?
Nick: It sucks.
Nick: How's your new book coming along?
Catherine: It's practically writing itself.
Nick: So was she ever a suspect?
Sheriff: Nope! There was some talk, but it never panned out.
Nick: What kind of talk?
Sheriff: Girlfriend.
Nick: What he had a girlfriend?
Sheriff: No! She did! But like I said, it never panned out.
John Correli: Did you kill Mr Boz, Miss Tramell?
Catherine: I'd have to be pretty stupid to write a book about killing and then kill him the way I described in my book. I'd be announcing myself as the killer. I'm not stupid.
Gus: I don't buy it! There's gotta be somebody there, who knows whats going on.
Nick: I know what happened alright! Catherine told me and everything she said has checked out.
Gus: You've got Goddamn tweety birds flying around your head! You think the two of you will fuck like minks, raise rugrats, and live happily ever after.
Dr. Myron: Do you believe Lieutenant Nilsen deserved to die?
Nick: I didn't know him well enough. I won't miss him.
Catherine: Somebody has to die.
Nick: Why?
Catherine: Somebody always does.
Nick: What is this? Some kind of joke?
Nick: What's your new book about?
Catherine: A detective. He falls for the wrong woman.
Nick: What happens to him?
Catherine: She kills him.
Nick: I'm in love with you already, but I'll nail you anyway.
John Correli: Were you ever engaged in any sadomasochistic activity?
Catherine: Exactly what did you have in mind, Mr. Correli?
Nick: What did Manny Vasquez call you?
Catherine: "Bitch" mostly, but he meant it affectionately.
Catherine: Got some coke?
Nick: I've got a Pepsi in the fridge.
Gus: Where in the fuck you've been? I went over to your place.
Nick: Easy, cowboy, easy. I wasn't there.
Gus: I went over last night, too.
Nick: No, I wasn't there either.
Gus: You fucked her? Goddamn dumb son of a bitch, you fucked her! Goddamn, you are one dumb son of a bitch.
Nick: Next time I'll use the rubber.
Gus: Everyone she plays with dies.
Nick: I know what that's like.
Answer: She is portrayed as a psychopath with an uncontrollable urge to kill.
raywest ★
I wouldn't say that she had an "urge" to kill. Rather, she was willing to "dispose" of people by killing them. She would kill people who were in her way or were no longer interesting/useful.