Some people reject God because they can find no evidence for Him which satifies both their hearts and minds simultaneously.
Then there are others who accept God in the basis of emotional or irrational reasons which satisfy their hearts, but leave their minds unsure.
These two groups of people have never found a satisfying answer to the question of their relationship with God.
Then there are yet others who have found the correct path which God intended for us: to accept Him and His message to us using our minds first and foremost, and the heart follows easily and naturally as a consequence.