A Rebbetzin in my neighborhood once told a friend of mine who was having an issue “never put anything in writing, you never know when it will come back to haunt you”. That was very, very good advice. And that was in a situation where she was willing to apologize for something that she wasn’t even in the wrong about. The Rebbetzin told her tell her your sorry if you wish just for the sake of Shalom but don’t put it in a letter because if things don’t work out, she could use that as an admission of guilt and use it against you.
The power of the pen is something to be very careful about, even if you mean to do good. One must be very careful with their words and what they choose to relate.