@PredatorKnight: Dude, calm the eff down. He has, what you sexually frustrated ones call, morals. Because he doesn't think with his dick, that's how women fawn to him: because he looks at them for THEM, not their goods. The aggressive "Alpha" types are typically found in hentai, anyway. If you're horndoggin' that much, read those. You'll feel better in more ways than one (not being an asshole, I'm genuinely offering advice).
Anyway, it's showing up to where the girls have some pretty extreme secrets. My bet's on the sister simply because they ruled her out from the very beginning.