My LO is experiencing bullying. Any advice?

My LO is 5, in kindergarten. She has a small class, and everyone is so wonderful. There is one kid who has been making my LO feel bad. When I pick her up from school, she says this kid is mean and tells her they don't want to play with her. And then they also tell other kids not to play with my LO.

I told my LO to still be kind to this other kid and to just find other kids to play with. Her teacher is aware and has been wonderful in this case.

My question is what should I do to help my LO understand that not everyone wants to be friends? And as hard as that fact is, she still needs to be kind and let it roll off her back. How do I get that idea through to someone so little? Any advice is appreciated.