There’s a difference between repentance and regret. “Godly sorrow brings repentance that leads to salvation and leaves no regret, but worldly sorrow brings death.” 2 Corinthians 7:10
Both are characterized by deep sorrow and distress but they are vastly different.
First, regret does not produce any real change, while repentance does. Regret is sorrow over the consequences of sin, but not over the sin itself. If there had been no consequences, there would have been no sorrow. There is no sorrow for how it grieves God. Therefore, as soon as the consequences go away, the behavior comes back.
Second, “worldly” sorrow stays regretful, while repentance moves all regret to the past. Repentance always makes us more able to accept and move on. We say: I deserved far worse than what happened. The real punishment fell on Jesus, and will not come on me.
Regret is all about “me”: how I am being hurt, how my life is ruined, how my heart is breaking. Repentance is all about God: how He has been grieved, how His repeated saving actions are being trivialized and manipulated.