The conflict in the Middle East has provided people living under Islam a small glimpse into the differences between Islam and Christianity, and the impact Christianity makes on the treatment of other people, even the openness of Christians (and armies from their country) to selfless sacrifice devoid of the promise of 72 virgins.
When Christ is lifted up for them to see and they are given good information, not propaganda and misinformation, they are like everybody else, they make good, rational decisions.
We can hope that conversions are sincere. Certainly the Spirit moves where it wills.
However, remember Spain. There were insincere conversions there by Muslims, who then proceeded to undermine the culture with Islam.