BTW the otherside is atheism, not merely a conversion to a new FAITH
"I contend we are both atheists, I just believe in one fewer god than you do. When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours."--Stephen Roberts
So if we pick a god we both disbelieve in then we are starting from the same place. I don't believe in Zeus. You don't believe in Zeus. We are both atheists when it comes to a belief in Zeus. So what would convince you that Zeus exists?
Whatever it is that would convince you that Zeus exists is the very same thing that it would take for me to believe in the God of Abraham.