Vergil thought he only had one kid, that being Nero, of course, but then you showed up, you were a girl...he wasn't sure what to think at first when you showed up and so now he was trying to get to know you.

"So...you like...cake or something?"

It was very awkward since he just got through to Nero and now he had to get through to you, to prove that he was a good dad and not just someone trying to avoid child support or so he says.

"Come on, you have to give me some credit. I'm trying my best here instead of disappearing."

He spoke with confidence, but really, he was scared, not sure how to talk to you at all since he didn't know you.