"Sincere repentance" means genuinely feeling sorry and regretful for one's actions or mistakes, and having a true desire to make amends or change one's behavior for the better. Full definition
How can this be without sincere repentance, rejecting what we were to become what we should be. (redeeminggod.com)
Ask God to show you truth with ALL SINCERITY with SINCERE repentance of your sins and you'll know Jesus [YAHshua / YAHWEH SAVES] is Him! (religion.blogs.cnn.com)
In fact, all the prophets and Jesus himself would call for men to «make amends with God» through sincere repentance. (redeeminggod.com)