Alright. I'll give you what I know and what I have to say about this:
1.Yes there is true love. You'll see it in married couples, your parents (if they're not divorced, otherwise never mind), and anybody you knew that got engaged and or married. It can also exist in music (people are always singing about it) , movies (they tend to be in exaggerated but it shows in certain ways) ,and books (like movies but maybe more realistic because they tend to give advice or stories basing on thier love life and or at least writing stories about it) and of course in real life. It's something that's out there and waiting to unviel (spelling problem?) and once it unveils, it's a beautiful thing because a great feeling comes with it unless you gave up on long a time ago because you couldn't take another shot at it,claiming it 'hopeless' when it's not. In your situation, yours would be unrequieted love from it seems....
2. You can't make her love you. It's like forcing her to well, do the impossible if you know what I mean. In this case, She has to choose in this situation. If she says 'Don't think about it' it can be warning sign that she's obviously like her relationship with one your close friend and she's trying to tell you that she only sees you as a friend n, noo matter how hard you try to tell or at least confess to her how much you like her.DO NOT go beyond the 'Just friend' zone as others have already avised you. It will ruin everything.
3. That's also her descision. Instead of confessing to her right now....support her and your other friend being together. A true friend should be happy for one another and if you come between them anyway, it will risk you of losing both of your friends because you'll not only end up losing them and blaming yourself somewhat in the end. So instead of trying to get her, realize whose needs more important at the moment: yours or theirs. Also try to think on what you would feel if you were her and put your them yourself in her shoes.
Okay that's all I can say for now, sorry if that was somewhat harsh instead of helping but that's the truth and if she did like you back, wouldn't she give you signs/hints and also be broken up with her boyfriend by now? For now, just deal with it and maybe she'll come around later when she's broken up with your friend. And I don't intend to say that she'll come running to you after that but maybe she might or maybe might not at all. What I mean to say is: DON'T set your expectations too high. It never works, at least that's what happened with me and schoolwork. Only time will tell.