Since a person is never completely free of sin, it is sometimes difficult to accept the fact that forgiveness is whole and permanent. Once a person has accepted Christ, the devil can do nothing except to make him doubt or feel unworthy. Satan knows that if he can cause doubt to spring up in the life of a believer, he can rob that believer of the joys of being a Christ-follower.
The best and most sure way to know that you are saved is the simple phrase: Because the Bible says so! If you have come to the Lord in repentance of your sin and asked Him to be Lord of your life, then you are saved. 1 John 1:9 promises, “If we confess our sins, he is faithful and just and will forgive us our sins and cleanse us from all unrighteousness.”
God loves you so much that He gave the life of His only Son to pay for your sins. Do you think that God would do that, and then not keep His promise? If you are still in doubt, please contact a trusted pastor who can help you through this. God bless you as you diligently seek Him!