No. When you truly repent, you are forgiven, when you give your heart to Jesus Christ, you are born again and saved. The two go hand in hand. Should you sin knowingly post receiving Christ, you still need to repent of that sin to be forgiven. God’s forgiveness and man’s are two totally different things. Should you sin against another, you must seek theirs and God’s forgiveness. When someone is saved, they will want to serve the Lord unless they have wandered or are insincere to begin with.