Do you know how I should go about asking my girlfriend with a bladder problem to wear diapers?
That's a tough thing to bring up. How do you think she'll feel about that?
I think she will be comfortable with it.
I think she might be a bit offended by that request. It's understandable though, given that adults generally don't want to wear diapers. I hope you two reach some sort of agreement on this.
She's going to love wearing diapers, I know it.
Maybe try to make a list of what you think are the positive things about having her wear diapers so you will have a stronger and more persuasive argument. She might still refuse, but at least you will be able to let her know why it's a good idea in detail.