Why do we question this?

LIES since Jesus was a life long fervent follower of Judaism! Just read your bible!!!!!!!!!!

Catholicism is the One True Faith and a person can know this with certainty by reciting the rosary every day with care.

Question what? You said question this... and provided no information related to what you are speaking of. 

Christians and Jews really do not know that god doesn't exist and that's just so sad! 

Well, I'd love to answer, but I'm gonna need a little more information.