Repentance with a contrite heart. We are told throughout Ezekiel that G-d will forgive us as often as necessary as long as we ask forgiveness and strive to do better. That's why Jesus went around telling people to REPENT!
The consequences of sin is death. Jesus paid the price (His death for our death) for our sins and in order to obtain salvation we must do our part and RECEIVE it.
As you know, many don’t believe they need a Savior - and God doesn’t force salvation on anyone - ONE MUST believe what Jesus did and RECEIVE what He did and repenting is what we do once we accept Jesus as Savior with a thankful heart.
What Jesus did was supernatural - what makes you think your ‘natural’ repenting can do anything supernatural? What if you forget any of your sins - are your saying you remember ALL your sins from the beginning? What if you sin and come across an unfortunate, untimely accident and you didn’t confess it? YOU have NO Savior - since you don’t believe His Blood washed them away.
We repent BECAUSE of what HE did for us! One can repent all day long but if one doesn’t believe that Jesus washed your sins away - it fruitless. The GREATEST sin is NOT believing that Jesus died for us. How do you repent on that one?