If you get to the point of saying the sinner's prayer, wouldn't you have faith prior to saying it? We are saved by grace, through faith. Isn't the moment we have faith, and the realization in our heart what the real truth is the actual moment we are saved prior to even saying "the prayer"? So many people (expecially tv preachers) always tell us to "say this prayer" without telling us to have faith and truly believe what is preached. It's like they use a magic spell for salvation.