Many denominations do not have "Confession" and do not believe it to be essential for their "Salvation." Why does the Coptic Orthodox Church believe in "Confession?"
Confession is the acknowledgement of sin before God. In the Orthodox faith, Private confession in the presence of a priest is an integral part of confession before God. We confess that we are sinners, not ignoring the work of God in our lives. We condemn ourselves and praise the Lord our God for His free grace in our lives. The priest serves as a father to us within the declaration of confession and he assists those who confess to him to carry on in an upright manner.
Salvation can be defined as the gracious deliverance of God, particularly through redemption from sin and its consequences. This is the salvation that Our Lord Jesus Christ procured us by His death on the cross.
There are many Coptic Orthodox books written on confession and salvation. I suggest you look in your church library and examine what is available.