I am not going to be my sister's baby's godfather.
Why don't you want to be your sister's baby's godfather?
I don't want the responsibility involved with being a godfather.
Being a Godfather is an important role in a baby's life. Someone shouldn't be a godfather if they are not committed enough to be one.
Well I might not want to be the godfather but I have bought the baby a lot of nice stuff.
It's important to talk to your sister about this role and how you feel. Being honest with her is the best thing you can do.