Superb letter. You have penned naina's mind very well. What is the position of sameer in Naina's life is also shown here. I think a letter like this will work better in their situation.
Even in real life also it is better to write a letter to show your issues to each other when u r having any argument with your spouse. Atleast you can express your mind completely when u write letter. I also use the same technique of writing a letter or message my husband when we have arguments. It has helped a lot to reduce the conflicts and more importantly except me and him no one else in the house will know that we are having an issue.
I seriously wish naina to write a similar letter to sameer in the show also.