Well my dear, there are 2 kinds of imposible love stories.
The first one is when love exists only by one side and on the other side, even if it exists, is not so strong as it should be.
The second one, is actually the kind of shakespearean style, when the 2 of them act as Romeo and Juliet.
So ... what is the solution on both cases?!
For the first scenario i will tell u about a good friend of mine from Pakistan, student at english literature, a guy that wants to be a writer.
He is young and very talented.
His english is excellent, but did not found the path so that he could become a writer.
He is also so deep in love with a beautiful girl from his country, but again he is not finding the path to go inside her soul.
I spoke with him few times and in the end we realised togheter that he should mix the 2 desires, being with the girl he wants and also being a writer, in only one desire.
He promised he will start writing, expressing the infinite love he feels inside his soul, writing only and only about love ... the love of his life.
If the trick works, the girl will understand one day that he is a fantastic guy and he deserves her attention.
For the shakespearean way of living the love story ... well .... what should i start with?!
The love exists on both sides, is actually infinite love, but they cannot live the story in the real life.
If you would analyze the stories behind great love poems, or other great love story novels, you would easilly understand thar behind what you read it was a great imposible love story from the real life.
The story does not need to end in the Romeo and Juliet style, but the fact is that we have an end, which is never hollywood style scenario.
Writing our feelings will make us understand better what is inside of us ... and also might be the way to survive.
So ... just write the truth and send the letter.