hmm... never got a letter... though judging by those I met it would start with:
"hello there!
Look, I'm terrible sorry! Really! You don't know how hard it is for me to tell you this! It's tearing me apart, but I have to say ... I don't like you that much.
Once again, I'm extremely sorry! Don't be mad at me now! It's a temporary thing honestly! Please, don't be mad at me!
Yours truly
An angry Canadian"
😉