Repentance is the renewal of baptism. Repentance is a contract with God for a second life. A penitent is a buyer of humility. Repentance is constant distrust of bodily comfort. Repentance is self-condemning reflection, and carefree self-care. (John Climacus)

Repentance begins in regret. The penitent is sorrowful. I recognize how I have contributed to another's pain and I experience the pain I have caused.

The Latin from which both repent and penitent are derived is paenitere which can mean regret, but depending on context can also be to displease, make angry, or offend.

I bet John's original text uses the Greek μετάνοια or metanoia which is usually translated as repentance. Literally after (meta) thought (noia), this implies a second-thinking, a new perception, a change of mind, and altered purpose.

The Lenten season is set aside for second-thoughts and redirection. In self-condemning reflection we confess the pain we have caused those we love most, and especially the pain we have caused God.

In confession we recognize our sin, seek forgiveness and, if we can accept God's forgiveness, we find renewed purpose and direction.