Answering your question is very simple. And I remember answering it once before. How would you ever find if you were wrong? I believe more important is that WHEN would you find if you were wrong. In an atheist case it would be after he/she dies. But then it would be too late. Someone did say that it is better to believe and then being wrong and find that nothing (Heaven or Hell existed) than not believing and then ending up there when it had already been too late.
Simplest way of dealing with that is that first of all you accept that you MIGHT be wrong and it should be very easy for atheists as according to them they would believe if proof was given. And then do one thing. Sometime in isolation only for your own sake say,
“Oh God, I am not sure if you exist or you don’t. However if you do exist then please guide me to the right path”.
Now if you consider then after saying these few words in reality you have not lost anything. You have put onus on God that if he does exist then he should show you the right path. I am not saying that he should make you Muslim, Christian, Hindu, Sikh, Jew or any other religion. I mentioned right path. And then keep you mind open to the possibilities in the future and I am sure God will show you the right path. And more importantly, before it is too late.