Why do you believe?

[The truth]

That's the point. Christ didn't just say he was going to rise from the dead and later his remains were missing. Other's saw him and beheld him after his resurrection. They touched him. They talked with him. He talked back with them. This was a real life experience. This was face to face communication. And not just between the twelve but an entire five hundred people saw him at the same time. Your grams claim of resurrection would have needed an eye witness. But according to your statement there was no witness. So, sorry your grams lied. Better get the posse ready.

So the difference is how many people witnessed the claim? What's the criteria?

You've answered it. More eye witnesses of a claim leaves us with greater evidence. Witness equals evidence I thought you knew that?