Tell her that you will accept her decision, whatever it will be, and will not bother her again if she does not find you interesting, but you need to know that she received your letter and read it.
(You won't believe how much more responses this short phrase will produce - it shows that you are really interested in her!
Search Internet for "Russian women", "Russian brides" or "Russian dating" to find more available resources.8.
It is highly advisable to join an e-group or forum designed for men seeking a Russian wife: you will be able to receive advice on any subject, first hand, from men that did the same thing, some of them were successful and are already married to Russian women. To marry a Russian woman, you must have a budget of USD 7.000-10.000 to make it happen, and the ability to travel to Russia.
Think about this process as finding a good job: you need to prepare a quality CV, do your homework and find out about the company you are applying to, adapt your CV to the needs of this company and position you are applying for, and present yourself well at the interview.