You say you're a nice guy. You respect women and would never cheat. You would never talk to a girl the way most other guys do. You're special. That guy that any girl would be lucky to have. Yet, no girl seems to want you. That's a little odd. Girls should like you. I bet you have a special someone in mind. I bet she's a friend— maybe even a best friend. She tells you all her fears, all her problems, and even sometimes cries on your shoulder after she fights with her boyfriend. What an asshole he is. You would treat her so much better. You would cherish her. You would be the best boyfriend in the world.
I bet you've told her how you felt. If not this girl, the girl you were obsessed with before. I bet she's acting weird now. Of course she is acting weird. She thought she had someone to talk to, someone to confide in, someone who cared about her as a person. You betrayed her. Everyone has been lying to you; you’ve been lying to yourself. You're not a nice guy. You're a guy who’s been letting a girl trust you, letting a girl take a little bit of the weight off her shoulders and give it to you. She trusted you with her problems and her emotions. No matter how many times she has told you: you're a great friend, showed no interest in you, or scooted away for more personal space, you decided to try and guilt her into being your girlfriend. Don't say you didn't. That's exactly what you did. You tried to take one connection and turn it into something else. She was sure about the connection. It was something stable. You ruined that for her by telling her how you feel.
Not only have you done that, but you've probably undermined her relationship. She can't trust your good advice now. It could have been self-serving and probably was. You told her you would treat her better. She loves a guy and all you have done is insult him and say he's not good enough. You've made her feel broken and you made her question her taste. Yet you think a guy that called her some name is the asshole? He may have called her something you wouldn't have, but you played with her mind, her emotions, her trust, and left her in a strained relationship with someone she actually likes.
Do you even know this girl? You have no idea how she is romantically and you only have one side of the story. You're in love with your own imagination. Take girls off the pedestal. All people are equal. Women burnt their bras and marched in the streets for equality. They don't need a boyfriend to feed them compliments all day and tell them how perfect they are. They have friends for that, friends like you. Friends they'll never date. They need an anchor to reality in a boyfriend and you can't be that until you admit that they have faults. They need someone who knows them, and you simply do not. You may know the secrets and you may know the fears, but you don't know her.
What can you do? You can start asking girls out and stop waiting for the right moment to do so. If they say no, move on to the next one. You don't need more friends to pine for, and I'm sure she doesn't need another guy waiting to tie her down. If you want tips and tricks on how to turn a friend into a girlfriend, you're looking for ways to manipulate someone, which is just another way to be an asshole. Stop being an asshole and ask a girl out.