He doesn't bother interrupting her as she tries to argue her case against him. Mostly, he doesn't really care to argue with her to begin with, but he also had only called her foolish. The rest she assumed he was implying as his conclusion of her, and she was more offended with what he might have said than what was actually spoken. She could fight with that all on her own.

"And yet not powerful enough to avoid death not once but twice, is that it?" Vergil looks down at her as they walk. "I'm sure you're quite special in your world. It's unlikely a being like the fox would have taken an interest in you otherwise. But raw power is not enough on its own."