yet now I am happy, not because you were made sorry, but because your sorrow led you to repentance. For you became sorrowful as God intended and so were not harmed in any way by us.
Godly sorrow brings repentance that leads to salvation1 and leaves no regret, but worldly sorrow brings death.
References for 2 Corinthians 7:10
See what this godly sorrow has produced in you: what earnestness, what eagerness to clear yourselves, what indignation, what alarm, what longing, what concern,2 what readiness to see justice done. At every point you have proved yourselves to be innocent in this matter.
References for 2 Corinthians 7:11