Always the thought provoking questions Octavia. I know of alcoholics, drug addicts, sex offenders, gay, transgender, and regular old sinners, etc. who have had their lives transformed through the power of Christ.
Receiving forgiveness and God's Righteousness, and indwelling Holy Spirit is instant, but growing up in Christ and conquering the "old nature" is a process that may take years.
So, yes I would, depending on the individual and after several years of consistent walking with God to prove that his "conversion" was the real thing, and not imaginary.
Listen to true life stories of people transformed at www.unshackled.org Cheers!