When you write your introductory letter to a nice Russian lady, it is better to use such greetings as Hello or Hi with her name. The word “dear” is equal to the word “honey” or “darling” in Russian and most likely would sound inappropriate for the first several letters.
Remember that nobody expects you to act like a super hero. She just wants to find the right guy, who would be reliable and understanding. It is most likely that a Russian lady registering with a matchmaking agency would look for a considerate person with a stable job. It is also preferable if he has no bad habits and wants to have a strong and happy family.
If you are a person she can trust, the one who is true and sincere, and steady, you are everything she needs. Just remember not to sound too good to be true. In this case she might feel the need to withdraw thinking that she does not quite meet your standards.
It is common for single Russian ladies to underestimate their personal value, and unfortunately this lack of self-trust interferes with their healthy desire to find compatible partners and create happy families. If you do not want to scare her away, be open and frank, but try not to dumbfound her.