"Godly grief produces a repentance that leads to salvation and rings no regret, but worldly grief produces death (2 Corinthians 7:10)." Consider the case of two men who betrayed Jesus. Judas, who for 30 silver pieces, sold the security and whereabouts of Jesus to the religions authorities in Jerusalem. Jesus, as we know, was arrested, tried and eventually executed. The other is Peter. On the very same night of Judas betrayal, Peter refused to acknowledge that he knew Jesus let alone that he was one of Jesus' closest companions. When the night is over both men are grieving. The Gospel says that Peter went out and "wept bitterly." The Gospel says that Judas tried to buy Jesus back and failing this he went out and hanged himself.
Both men were grieving their betrayals. One suicides the other weeps. One separates himself from the community and from life; the other isolates for the night but stays connected to the community. One goes beyond further help and the other becomes the leader of the Christian movement. That is the difference between godly grief and worldly grief. The godly grief leads us to sorrow and change and reconnection. The worldly grief leads us to despair.
There is nothing that separate us from the love of God in Christ Jesus our Lord (see Romans 8:31ff). When we fail, when we betray those we love, when we turn our backs on the way of Christ, we also have two choices. We can either repent (change) and turn back to the one who called us (Jesus) or we can despair. I choose life!