Is regret alone sufficient for the forgiveness of sins, or must all conditions of repentance be fulfilled?

Regret is the fundamental pillar of repentance, but it is not sufficient on its own. Rather, all conditions of repentance must be fulfilled for it to be valid, which are: regretting what has passed, intending not to return to the sin, and immediately abandoning the disobedience if one is currently engaged in it. Repentance is not realized except through regret, abandoning the sin and forsaking disobedience, and resolving not to return to it.