How do we know the doctrine of conversion is true?

The doctrine of conversion is evident in Acts 19, where many in Ephesus recognized their past sins and publicly repented by confessing and destroying their occult practices. True conversion involves not just verbal acknowledgment but also tangible actions, such as the burning of their magical books, symbolizing a break from their former lives. This aligns with 2 Corinthians 5:17, which states that in Christ, we are a new creation. This transformation is a sign of the Holy Spirit's work in the believer, indicating the truth of the conversion doctrine.