I'm not going to make confident assertions about what would change my mind. There are too many factors. But I can tell you something that would, in my eyes, decrease the probability that Christianity is true.
One thing that would hurt the probability of Christianity for me would be if skeptics could come up with a halfway convincing story about how Christianity arose. Swoon theory? Come on. Jesus stripped on 100 pounds of grave clothes, pushed that gigantic stone out of the way, and put a flying tackle on the Roman guard, after being left for dead because of a crucifixion? Hallucination theory? Lots of problems. The disciples stole the body? Why? So they could get martyred for something they knew was false. Legendary development? Why does Luke know so much about all the city governments in the Mediterranean world? Jesus never even existed? How come nobody has come up with the theory that Socrates never existed? Jesus' evil twin took over after he was crucified? Getting desperate aren't we?
Of course, I know all about the Humean argument that anything's better than accepting a resurrection. Yes, rationally, one could be a skeptic about the supernatural origin of Christianity while admitting that there isn't much out there in the way of naturalistic explanations of the founding of Christianity. But why do all those theories have such ghastly problems?