Regarding salvation: Most Christians (Protestants, Reformed and etc) characterize the dogma concerning the Pope as Christ's representative head of the Church on earth, the concept of meritorious works, and the Catholic idea of a treasury of the merits of saints, as a denial that Christ is the only mediator between God and man. Most Christians believe that faith in Christ alone is enough for eternal salvation (as stated in Ephesians 2:8-9), whereas Catholics believe "faith without works is dead" (as stated in James 2:20). Most Christians believe that practicing good works attests to one's faith in Christ and his teachings. The Roman Catholic view of the means of salvation was believed by the Christians to be a mixture of reliance upon the grace of God, and confidence in the merits of one's own works, performed in love. The Reformers posited that salvation is entirely comprehended in God's gifts, (i.e. God's act of free grace) dispensed by the Holy Spirit according to the redemptive work of Jesus Christ alone. Consequently, they argued that a sinner is not accepted by God on account of the change wrought in the believer by God's grace, and that the believer is accepted without any regard for the merit of his works for no one deserves salvation.
Our salvation must be true from the beginning or else, you can play Christian and not be saved. We can fake other people but we can't fake to God. People can possess an intellectual understanding and knowledge of the truth and yet not be saved. A person may remember exactly when they made the "decision" but that doesn't necessarily mean anything. By itself, even conviction of sin is not a proof of salvation. We all can claim to be a Christian, and we all believe that the root of the matter is in us and the seed of God is in our hearts.
Galatians 6:3 "If anyone thinks he is something when he is nothing, he deceives himself."
James 1:26 says, "If anyone considers himself religious and yet does not keep a tight rein on his tongue, he deceives himself and his religion is worthless."