In your opinion what causes christians to believe in Jesus

[Sheldon]

Okay then come up with your own scenario bro. As long as you illustrate what you mean by objective evidence of possibility. Surely, you know what you're asking and can give an example?

How about this one...

Some of my neighbors claim there is at least one wild boar living in the forest just above my house. I have never seen it. 

I have good reasons to believe it is possible.

~ My neighbors have no reason to lie. They might be mistaken, so I take their word as evidence, not as proof.

~ Wild boars are native to my prefecture, although they are usually farther up in the mountains. 

~ Quite near my house I have seen evidence of some large animal digging up grubs. 

So I would say that this constitutes objective evidence of the strong possibility that there is a wild boar around here. 

Is this the kind of thing you're thinking of? I'm curious about what you mean.

Well again, we already know wild boars are possible, it is an objective fact. So the claims are not really the same. I have no problem with people speculating about what kind of evidence they'd consider sufficient,  or sufficiently objective for a deity. However given how many deities humans imagine to be real, and how many versions of ostensibly the same deity, I am not sure what I would achieve, surely better to ask the person who seeks out people who don't share the belief, to make claims about their beliefs, to offer their reasons. 

No one is obliged to share anyone else's threshold for personal credulity after all, we can only ask why they believe, what their best reasons are, and then decide if we think we find them at all compelling, and why.