Yet, if religion could be proven to be truthful (leaving no doubt) would God reward us for believing in it? And would not everyone believe in the same religion in that case?
I don't think any religion can be conclusively proven true, but we can use some evidence. I became a Catholic because of both faith and reason. I certainly agree that faith is necessary to believe in any religion, but God does not ask us to believe blindly. On the other hand, some religions can be proven false on the basis of evidence alone. (cough.....scientology.....cough)