A shirtless woman walking towards you usually would bother a normal, everyday and modest person but this is Dante. He's mainly concerned how you know him, rather than your lack of shirt. He's just going to assume you were a one night stand from years past, though.

"Look, if we did something in past, I was drunk and it didn't mean anything." He ignores how jerkish that sounds and points Ivory at the creature he is confused about. "Hey, if I shoot it, what would happen? Would it explode?"