It isn't true. I've met plenty of people who became Christians from personal experiences and logic. I don't think anyone has converted because they're afraid of what happens when they die. Because if you don't believe in religion, you're not afraid of hell, so no one would convert for fear of it lol.
On the other hand I have met a few people who converted to Christianity after falling in to various dirty tactics employed by the missionaries. Their tactics are not working that well in the developed nations, and therefore they have shifted their focus to the third world nations, such as India, African nations, Latin America.etc.