Letters of love are said to be the most often kept and the most often burnt. linkshare It's probably the hardest thing to write even for a professional writer. The whole magic is not the words you write, but the way you write. While reading, the receiver must feel all you feel, your sincerity and your love. It's surely not an easy task, but everything is possible.
Of course you can make the most of it.
Marriage is a different thing. You can write anything you want, express as much and as strong feeling as you want. If you are married, that means your husband or wife loves you and there's no danger to ruin anything.
You should also pay great attention to spelling. Misspelled words are symbols of carelessness. It won't take your time to look up a questionable word in a dictionary.