What would convence me that god exists? Don't know, and don't care. Assuming we are talking about a god with some sort of omniscience and omnipotence (doesn't even need to be the "can break laws of logic" type), then that god knows very well what it would take to convince. Since I haven't been convinced, it tells me that god hasn't provided that information. Given that god is omnipotent, and has the ability to provide it, then I conclude that god either doesn't want or doesn't care that I believe that he exists. If god doesn't care whether I believe it, then why should I?