Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come.~II Corinthians 5:17
5:16-21 The renewed man acts upon new principles, by new rules, with new ends, and in new company. The believer is created anew; his heart is not merely set right, but a new heart is given him. He is the workmanship of God, created in Christ Jesus unto good works. Though the same as a man, he is changed in his character and conduct. These words must and do mean more than an outward reformation. The man who formerly saw no beauty in the Saviour that he should desire him, now loves him above all things. The heart of the unregenerate is filled with enmity against God, and God is justly offended with him. Yet there may be reconciliation. Our offended God has reconciled us to himself by Jesus Christ. By the inspiration of God, the Scriptures were written, which are the word of reconciliation; showing that peace has been made by the cross, and how we may be interested therein. Though God cannot lose by the quarrel, nor gain by the peace, yet he beseeches sinners to lay aside their enmity, and accept the salvation he offers. Christ knew no sin. He was made Sin; not a sinner, but Sin, a Sin-offering, a Sacrifice for sin. The end and design of all this was, that we might be made the righteousness of God in him, might be justified freely by the grace of God through the redemption which is in Christ Jesus. Can any lose, labour, or suffer too much for Him, who gave his beloved Son to be the Sacrifice for their sins, that they might be made the righteousness of God in him? ~Matthew Henry’s Concise Commentary
Hell is full of sincere, religious people, never born again, and heaven is full of immoral people who repented and believed in Christ.