True repentance goes on to work sorrow for sin. The heart of a repentant person is touched with deep remorse because of their past transgressions. They are cut to the heart to think that they have lived so madly and so wickedly. They mourn over time wasted, over talents misspent, over God dishonored, over their own soul being injured. The remembrance of these things is grievous to them. The burden of these things is sometimes almost intolerable. When a person sorrows like this, you have the second step in true repentance.