It's too bad many people do not have any assurance of salvation at all. It's a great thing to know, and for others, that does not at all mean people can live like hell, because their sins are forgiven. Not even remotely close.
Romans 1: For I am not ashamed of the gospel, because it is the power of God that brings salvation to everyone who believes: first to the Jew, then to the Gentile. ...
... 2 Timothy 12 (b) Yet this is no cause for shame, because I know whom I have believed, and am convinced that he is able to guard what I have entrusted to him until that day.
13 What you heard from me, keep as the pattern of sound teaching, with faith and love in Christ Jesus. 14 Guard the good deposit that was entrusted to you—guard it with the help of the Holy Spirit who lives in us.