Religion is the most personal thing in the world. It is nobody’s business to approach other’s belief in any way. Simply put: It is a bet, everybody is betting his life on his belief no matter what it is. When it is time to know if we won or lost there will be no second chances.
In Quraan God made it very clear that nobody is to be compelled to believe in Him. Why: Because God wants people to believe in Him out of deep conviction which is reached by observing, thinking and researching. Once this happens nobody can remove the belief from the heart no matter what. But those who are forced one way or the other into a belief will come out of it as soon as the pressure is off. A good example is places which were invaded by the so called “Muslim Armies” who turned away from Islam as soon as the armies went away.