How do I convince my mom?

I was talking to my mom about pit bulls. I asked her if we could get her one once my old dog dies. She said no and I asked why. She said "To be honest, I don't trust them" So my question really is, how to I explain to her/ show her that they can be trusted just as much as the kind of dog she wants, a bull mastiff. I don't want her to say we can get one or anything like that, I just want her to realize that they can be trusted just as much as other dogs.