How do we know regeneration by the Holy Spirit is true?

Regeneration, or being born again, is a fundamental doctrine in sovereign grace theology, clearly articulated in passages such as John 3:3, where Jesus states that one must be born again to see the kingdom of God. This work is sovereignly performed by the Holy Spirit, who instills new life into the believer, enabling them to understand spiritual truths and embrace Christ. The evidence of true regeneration is manifested in a changed life—one that craves righteousness and exhibits fruit consistent with a new creation in Christ. As outlined in 2 Corinthians 5:17, if anyone is in Christ, he is a new creation; the old has passed away, and the new has come. Thus, regeneration is a reality that is verified through observable change in the life of a believer.