Maybe you've over thinking and seeing things that aren't there.
I mean YOU think that this is her attitude towards men and sex.
How do you know this isn't just a mask. You know a girl who's made by society to hide her sexual desires and pretend she isn't interested in sex, so she doesn't appear "easy"
I wouldn't ask her about getting into a relationship with me, because I'm with Chase in the idea that you should never bring that up with a woman. She should chase the relationship. And as Ricardus has written, if you want her to be your girlfriend, don't make it explicit.
I don't mean talk about being in a relationship, I said talk about being romantically together, meaning talk about her coming to your place at night to watch a movie, have dinner, etc.
I've hooked up with her plenty of times but no sex.
Okay, this changes things
A LOT!
This may mean you either missed and escalation window and her attraction hast started expiring, or she's started to go into auto rejection, or maybe she like you and wants you to be her boyfriend - and that's shy she's taking it slow with sex, she doesn't want to "rush" things or appear "easy". This is the case when girls see you as "boyfriend material" they give you a lot of resistance towards sex the first month or so.
The only way for you to know that is to arrange a date with her (just the two of you) and since you know each other and have "hooked up" you should ask her to come to your place and she should agree.
Then you start kissing her, after some time you start kissing her jaw line, then go up a bit to the ear, then go down to her neck, then go down to her collar bone.
And see what happens.
If you make out and kiss each other, but every time you start going a bit down with you kisses, if she appears excited but nervous and putting up resistance - then you'll know that she wants you a s boyfriend and that's why she's putting up resistance towards sex.
If she doesn't want to come to your place, or you don't make out, etc. - you know that you're screwed and to just move on to the next girl.
Don't think she's the most beautiful girl with the best body and best personality.
That's just putting her on a pedestal and that's WRONG!
I mean I doubt you've met or dated lots of girls (meaning at least 10 girls in the past year or so) to be thinking she's so special. That's just because you haven't got much experience.
I used to think that some girls were that special and rare, till I found out there are girls much more beautiful, with much better bodies, and with much greater personalities. And then I found out there a girls better then those. And at the end I found out that even the hottest girls are just people with normal people problems dreams, ambitions, feelings
(well that one I'm working on since I've said it a few times that I have a problem of seeing girls as more than sex objects and as having feelings), jobs, studying, family, friends, hobbies.
They get more attention and want to be treated as normal people, well maybe not some divas they'd want special treatment.