Great story about John Wesley that may be apropos:

Wesley was an ardent preacher and scholar, but secretly felt he was a fake.   He had lots of knowledge and was doing all kinds of works, but didn't really feel like an authentic Christian.

Later, he went on a voyage and there was a storm at sea.   Very frightening in those days, and Wesley was near scared to death of dying and ashamed of it to boot.   Where was his faith, he wondered?   

He noticed that some German Christians of another sect were together singing hymns while the storm raged.   They seemed at peace.   How could this be?   What did they know that he didn't?

The storm passed, and the next day, Wesley swallowed his pride and approached the German pastor, inquiring of him why he and his people were not afraid.

The pastor said, "you either believe that Jesus died on the cross for your sins and gave you salvation, or you don't."