All Sinned
The first thing we need to think about is that no one deserves heaven. No one, not you, not me , not Paul, not John, not Peter. Forgiving sins and letting people into heaven is God’s decision.
Ephesians 2:8,9 For by grace you are saved through faith, and that not of yourselves. It is the gift of God, not of works lest any man should boast.
Second. We forgive others who have sinned against us. That does not mean that suddenly they need no punishment here on earth. A robber forgiven by the owner still should serve a jail sentence. Forgiveness is us refusing to take punishment into our own hands. Justice is from the government. Punishment is applied from them to preserve a civil society. It is ok to hope for that.
Do you know something? Only God knows who is really a Christian, because he knows the heart of man. We can know about our own heart, because Proverbs tell us to search our hearts and guard our hearts. Other people—we only know what they tell us.