There are a couple things I recommend:
Build Sexual Tension to an unbearable level
Friend zone her (Only works if she didn't do it to you already)
This sounds really weird but instead of allowing her to put you in the friend zone, you tell her:
"I am glad we are friends."
"It's good to have female friends like you."
All the other friends lines where you consciously put her in the friend zone. This only works because you don't let her choose what you guys are.
Then all you do is continue to play the attractive guy, go hang out with other women, your actions and behaviors should show you are a hot and available mate but not to her. It's kind of playing take away, she is just a friend and while other girls are sleeping with you.
Warning: Friend Zoning a woman is a difficult maneuver and it only really works if you aren't already friend zoned by her already. So if she already considers you "just friends" you should not use this.
Thoughts on your actions:
You went AFC. You bought her a nice present for her birthday, WHY? She isn't your girlfriend. You can't buy a woman's affection (unless she is a gold digger, never met a nurse that was a gold digger), if she was attracted to you before nothing changed from "a wicked present".
It's not about just building a connection. That is no big deal, we build that with 1000s of people through out our life, so what if you built a connection with her. All you have with this women is a connection.
You mention slut like every woman isn't sexual. She is fucking that guy because she needs to get laid. I don't feel any woman is "slutty", I don't care how many men she has slept with. It's not a bad thing for a woman to be comfortable sexuality, it's bad when she is uncomfortable with it. She wants to get laid and she is "single" so what is your problem? Go fuck her, she obviously wants sex.
Note: In my experience aspiring nurses avoid relationships a lot because of their commitment to their goal, becoming a nurse. This isn't every woman, she may just enjoy "what they have." Without witnessing it I can't tell you what she is thinking.
You care too much, you care more than her and because of this she owns all the power in the interaction (The person who cares the least owns the interaction). This is why I thought about using the concept of friend zoning her because it gives you the power in the relationship.
If she keeps telling you he isn't her boyfriend it's likely because she doesn't want him to be (it sounds like a disqualification) but I could be very wrong on this.
Have you read her body language?
Is she sexually attracted to you?
Quote:
We watch movies together, go to the bars together, I've made her dinner before
^^^ These are friend activities if you haven't hooked up yet, so you may be too late. Girlfriends do this stuff together all the time. If you are watching movies together and you haven't tried to fuck her it's your bad. I did this earlier this year with a fly dame I was stuck on, if I would have made a move things would have worked out. This is likely the case for you, you probably became to much like a friend and unless you build sexual tension so there is that between you guys you are likely dealing with a friendship only.
Getting into a relationship isn't my specialty but you can't get in a relationship if she doesn't want to fuck you, this is an important element to every relationship. Every relationship that goes sour starts with sex stopping. So I'm re-emphasizing the importance of sexual tension.
Peace and Love,
Vic