I'm not sure how adopting religion can change your innate personality, except perhaps that for many people, it motivates you to live to a higher level of morality. But for shyness? No. Curing shyness takes lots of practice with stepping outside your comfort zone and being willing to risk looking silly.

Personality is innate. I have two kids; one was happy-go-lucky and easy-going as an infant. The other cried and complained more easily, and was more demanding. To this day, those characteristics may vary a little depending on circumstances, but they are generally intact.

Changing the way you look at things has a lot to do with perspective, though. Being exposed to a variety of things can change your perspective, but not your personality.

__________________