Dear Bully,
I was wrong. You've started spreading rumors about me, and it's just as bad as if you were calling me names to my face. In fact, it's even worse. You've caused a few of my friends to turn against me. Even though I don't know exactly what you're saying about me, I know it must be pretty bad to isolate me.
Luckily, not even your words could turn my best friend against me. We've been friends for six years, you're going to have to do a lot better than some viscious rumors to break us apart.
