Wrong, wrong and wrong.
We are only forgiven of a sin when we repent of that sin.
If your statement was true...why would we need unlimited forgiveness of sins? Why wouldn't O times do?
See why that makes no sense?
Christ died on the cross to establish ...grace....a umbrella of forgiveness when we repent and ask God's forgiveness...in Jesus's name...... Nothing about it is occurring without our repentance.
So, if there is some sin that you fail to confess or repent of, you are not forgiven of that sin?
Better be certain that you know what is every sin in the Bible and be certain that you confess all of them before you die!
Sin is the transgression of the law (1 John 3:4).
Yet I am not condemned for violating the food laws in the Old Testament (1 Timothy 4:1-6); and therefore there are sins that I can commit and yet not be condemned by them, even if I never confess them. Eating shellfish or pork, according to 1 John 3:4, is a sin; however it is not a sin according to 1 Timothy 4:1-6.
Therefore, do I need to confess and repent of violating the food laws of the Old Testament in order to be forgiven?
The reality is that we are not under the law (Romans 6:14), are dead to the law (Romans 7:4, Galatians 2:19), and are delivered from the law (Romans 7:6) as concerning condemnation.
The repentance that leads to salvation is the change of mind concerning Christ that says, "God be merciful to me a sinner" and that believes in Christ and what He did on the Cross for our salvation, dying in our place.