With best friends or even friends for that matter, you have to be so so careful. For a start, it's usually better if they do like you back - the same way you like them. There's no point in thinking you have a chance because she's realised she needs to be treated better, don't let her "settle" for you simply because you will treat her right - things will go to crap if you do that!
My best friend and I got together for a little while, but it all started because we did like eachother a lot, in the end though - best friends are people you probably will always fall for, because best friends will love you no matter what. However, if you take the risk of dating, you're also risking friendship and a lot of other things. If you're not mature enough to continue a friendship once you've broken up, your whole life will change - the people you see, etc etc.
I don't know really, I don't think I would tell her. It could make things really awkward if you aren't sure that she feels the same way.
To love is to suffer. To avoid suffering, one must not love; but then one suffers from not loving. Therefore, to love is to suffer, not to love is to suffer, to suffer is to suffer. To be happy is to love; to be happy then is to suffer, but suffering makes one unhappy; therefore to be unhappy one must love or love to suffer or suffer from too much happiness. I hope you're getting this down.