Isaiah 64:6 But we are all as an unclean thing, and all our righteousnesses are as filthy rags; and we all do fade as a leaf; and our iniquities, like the wind, have taken us away.
So what must we do then to be saved?
Acts 16:31 ... Believe on the Lord Jesus Christ, and thou shalt be saved, ...
You can be 100% sure of heaven!