Researching psychopaths...............

So I have been writing 'Prisoner 702' for a while now and the further I get, the more interesting she gets.
Now I won't tell you too much because I don't want you knowing too much. 
I have been researching psychopaths recently, I wanted her to have the creepiness of Hannibal Lector but the insanity of The Joker, with such a high IQ it's impossible for her to be placed. To be honest, I have found it very interesting, a little disturbing but very interesting. For example, they aren't capable of feeling love, so I have to be very careful because if she does come off as a psychopath, she can't be seen as falling in love with Special Agent Greenway.  Although, the more you read it you'll see there is something there. Not love in the traditional sense, not like Harley Quinn and Joker.  Psychopaths do lure unsuspecting people into a false relationships for their own gain, to be honest I don't think I want her to be that evil, plus Dallas Greenway is not that weak that he could be fooled into such a relationship.  He's far too clever and smart for that, that doesn't mean he's not susceptible to her mind games though, that would make a very dull story.
Now I was wondering, if there is a way of her being too evil, now what I want from her is to be hated, but lovable at the same time.  I was her to lure you into her trust only for her to shock you and shatter the trust you had in her. 
I have found some really cool ticks for making her creepy, like her face for example.  If she was to smile all the time like Joker, that could imply she is just insane and the interlect she has would make no sense at all.  Now if I gave her a vaguely amused look most of the time, that would almost make you feel she's patronising him all the time.  Like everything is just funny for her, like she takes nothing he says serious, like this is some amusing game for her.  Like Hannibal Lector no? Also while watching 'Silence of the Lambs' for the umpteenth time, I found Anthony Hopkins didn't blink that much at all, now I think about it, I'll have to watch it again and see if he does.  I thought, those wide, unblinking eyes, she has soft brown green eyes, the green part really stands out, so having a set of those eyes just looking at you, I think that would be very uncomfortable.
As for how evil I'm going to make her, well it's a little hard, I'm quite a nice person so what I find evil and unkind might be a little, tame?  It's the end I think will be the test, it will either make you hate her beyond repair, or think, oh my gosh why the hell did she do that?
I think I like Agent Greenway so much I'm in two minds how to end it, I can't have a happily ever after, that would be pants, I mean really pants.  I think I will do this ending, it will be great, but just mean, but when you read the novel and get to know the characters you'll understand, so when it's done, please don't hate me.  What I do, I do for a good novel.

TTFN my lovlies.