Your situation is very typical....Everything seems to be going alright....both of you seem to be deeply in love, nothing will ever stand in between you, but all of a sudden BAM! the woman decided to end it.... simple , like that,,,out of the blue.

Women are women , wherever they are. If they feel that you no more have that attractive quality, they once loved about you, they'll leave. If they feel that your comfort/rapport level misses something, they will leave. If they don't feel trust for you, you won't go any further. If you supplicate to her, or became "mr. nice guy", bought her all sorts of gifts and/or flowers/drinks, they will put you into the "provider" category and not the "lover" or the "MAN" category. Instead they'll empty your pockets and leave you with a broken heart. This may sound illogical/cruel but it's simply the fact and men have to deal with it.

Now I'm not saying that your case falls under one of the above or something else, as there are some details missing to judge right now. But from her letter, I can tell you that you fell into the "let's just be friends" zone. You displayed something that made her put you into that zone, and guess what? girls/women don't make love to people they put in that zone. She sensed that you wanted more, she likes you so much, as a friend that is. Infact she is so worried that you will get hurt by her letter, and is praying that that wouldn't happen and you may still remain friends. She doesn't wanna lose you.

By all means DON'T tell her that you love her now and want to marry her! You know what'll happen if you did that at this time? She'll simply disappear! You won't be able to get a hold of her be it offline or online.... You will further scare her off.... she will feel so sorry deep inside her that she will lose such a wonderful friendship, but she SHOULD act like that if you continued pushing. It's hard to get out of the friendship zone, but if you act normal, and not mention what happened (even better if you tried to convince her that she got you wrong) and gain her trust that this won't happen again, not by telling her but by acting alone, you'll have a chance. Just this time try to meet her more frequently (offline) but without being pushy, just to do some stuff only "friends" do. No dinner, no dates nothing,,,,just cool fun stuff like visiting a museum, skiing, mountain climbing etc.. Then you can re-game her again, but this time in the right way.

Also consider having photos of you with some of your other cool female friends on your digicam or mobile phone all the time, and accidentaly (supposedly) making her see them. Maybe work it out so that she hears/witnesses some convo between you and them. This has proven many times to get guys out of the friendship zone. You will know by her reaction. I can't stress this enough guys, when women see you surrounded by other women, they instantly get attracted to you without them knowing it, even if that is the only thing they know about you.

If however you can't do the above, then I'd suggest to move on. It is even better for you .... go find 10 other women ASAP and get physical with them. You will cure yourself, and better yet if you still have feelings for her after that (which is very rare), you would know she is your soul mate.