Suppose Jesus personally appear before you, explain and DEMONSTRATE to you what you fail to understand. (But wait, that does not happen)
Suppose with faith of a mustard seed, Christians manage to move the mountains, heal all the amputees, and the rest of the sick in the world just by prayers. (But wait, that does not happen)
Suppose every time there is a natural disaster, everyone die except the Christian and their church (But wait, that does not happen)
Suppose bible contain some information that is truely impossible to know at that time, for example, the germ theory in great detail. (But wait, that does not happen)
All the above would make the God hypothesis very believable, even though you will probably not be certain.
That is, if they have convincing objective facts to present. How exactly do people cook, without food? I am open to the idea they may find food someday, somehow after so many years of attempt.
As an atheist, I am just totally pessimistic about it. I think most atheist you find is open to persuasion.
---------
You can asked a religious what will convince them otherwise, and they will usually show no such possiblity.