Pascal's wager is what your question paraphrases and it is really a simple risk assessment formula. It tries to say that if there is a non-zero probability of something being true, and if it has infinite negative consequences (or infinite positive consequences), and also requires little to no sacrifice to avoid or attain those consequences, then from a risk management standpoint, you should bet on it being true.
Sounds sensible enough at first glance... but its reasonable to conclude that every single religion has a non-zero probability of being true, and that there are other possible infinite afterlives which will either be better for me than Christian heaven, or worse for me than Christian hell (they both are pretty generic). By the rules of the wager, I should find the religion which poses the greatest risk (or reward) to my eternal well-being and believe in it, instead. So if one wants to bet their life according to the wager, it should hardly be a given that Christianity is the religion to choose. So, what if you are wrong? I hear Islam's afterlife is supposed to be pretty cool (at least for us men).
The other portion where it fails, is the assumption that the sacrifice of this life, is no sacrifice at all. Indeed, I will have given up the only existence and chance at well-being I may ever have, living according to a philosophy I don't actually think is true. I do not think this is a trivial sacrifice, and it is possibly the largest sacrifice that its possible to ask of a person. The actual sensible choice, is to attempt to discover what is most probably true, and live according to what ever that is.










