Isn't it strange how some DO freak out over anyone expressing assurance of their salvation? I mean, you would think that they would be happy to hear that a person has complete faith in Jesus Christ, follows Him and demonstrates with their lives that God is at work conforming us to the image of His dear son, right? But, how DARE we do that when we aren't Catholic! We're not supposed to be able to do that, therefore, it MUST be a false Jesus we follow or a false gospel we believe. They don't have that assurance and have been taught NO ONE can know they are going to heaven when they die.
That is why we face such resistance day after day here. To admit we are right would be admitting they are wrong - and some are simply incapable of doing that. Their pride keeps them from accepting the true gospel just as it prevents them from accepting the grace of God that brings salvation. It means humbling oneself and letting go of the false idea that we can become righteous through our actions and way of life. It means seeing those works as the filthy rags they are and trusting in Jesus Christ completely to redeem us. But you are right, there is a peace that passes all understanding when we KNOW we belong to Jesus - that HE is our shepherd and He has redeemed us and we will be with Him for eternity - an eternity where we can praise and glorify Him for His unspeakable gift!