Yeah, we "know" he does it, but we don't actually see it much. I think the only confirmation in the first few volumes is when he's about to hit on that one girl big time early on, then finds out that she has a boyfriend and backs off(though it's debatable whether or not he would have backed of that fast if he hadn't thought she was Doku's girlfriend), and then the chick who ended up being a youkai, but, IIRC, he already knew she was a youkai assassin before letting her in.