A little bit of a background: I'm not a player. I'm a romantic, even. I don't use seduction so I can "bang a billion hotties" or any of that stuff. I use it so that when I find the woman I'm going to spend the rest of my life with (whoever the hell she is), she doesn't think I'm a needy jackass.

Anyway, I'm sitting in my dorm room, and I can't help but bring my thoughts back to one of the girls I'm seeing. Why? Because I can't figure out if she likes me. As a well-read, experienced (relatively) seductionist, I know that she is just from all the obvious IOIs. But that doesn't change the fact that the more primal part of my brain just isn't sure yet. I've delayed our first kiss until the next time we see each other, so there's nothing technically overt yet. Yeah, sure there has been plenty of incidental kino, following the Dicarlo escalation ladder, and it's obvious in other ways as well. Still, nothing overt.

Now, to get to my point I'm sitting in my dorm room obsessing over my next move, for the simple reason that I'm not 100% sure. This makes me focus on her, and plan my next move. This focus is an investment. And according to founding father and notoriously successful ladies man Ben Franklin, investment leads to attachment. It's a simple fact that you care about things you invest in. Considering how well I've run this seduction "operation", I would say that she undoubtably thinking the same thing.

TD;DR: If you make girls wonder if you're into them, they will wonder about it, leading them to focus on you.