How do we know that the forgiveness of sins is possible?

The certainty of forgiveness rests on the completed work of Jesus Christ on the cross, where He bore the sins of the elect and satisfied God's justice. Hebrews 9:22 states that without the shedding of blood, there is no remission of sins. This indicates the necessity of Christ's death for our justification. As believers, we are assured in Romans 5:8 that while we were yet sinners, Christ died for us, affirming that our forgiveness does not depend on our efforts but solely on His grace and sacrifice. Furthermore, Ephesians 1:7 proclaims that in Him, we have redemption through His blood, the forgiveness of our trespasses according to the riches of His grace, showcasing the depth and security of our forgiveness in Christ.