yeah lustful will take the longest to 3star if you're going the nutters route like I am, you have to let them force themselves on you effectively, and it's a lot of times like everything else but I don't feel like it's 50 like it is for everything else, probably cause that would take too bloody long. Really wish the other girls could be 'alarm clock's' for you as that's the only reason Lin got to 3 star lustful. All the other stats are 3 starred up to and including Maria. I'm getting there very slowly but very surely.