Doyle: "Oh. Well, its all going to be okay. (Cordy slaps him)What was that for?"
Cordy: "Why didn't you tell me that you were half demon? I thought we agreed that secrets are bad!"
Doyle: "I wanted to tell you. I was afraid. I thought if I did, you'd reject me."
Cordy: "I've rejected you way before now! So, you're half demon. Big Whoop! I can't believe you'd think I'd care about that. I mean, I work for a vampire! Hello?"
Doyle: "It's true. I just..."
Cordy: "What do you think I am, superficial? - So you're half demon. That's so far down the list, way under 'short' and 'poor'! - Is there anything else I should know?"
Doyle: "The half demons thing is pretty much my big secret."
Cordy: "Good. That's out. It's done. - Would you ask me out to dinner already?"
I think Doyle really cared about Cordelia and towards the end Cordy definately had some fond feelings for Doyle. I don't think the half-demon thing would have been an issue.