To the best of my knowledge there is no such a title officially given to the Blessed Virgin. Yet I claim we duly may call her Our Lady of Good Repentance, and surely there is no better time to reflect on Mary and repentance than the Lenten season.
For a start, let us remember that in every Hail Mary we acknowledge our sinfulness in a most humble way, asking her powerful and efficacious intercession: Pray for us, sinners, now and at the hour of our death. In recognizing that we have sinned we remind ourselves the need of conversion; in asking for help, we admit that such a transformation is beyond the scope of our own strength, and thus we ask for God’s mercy and grace.
Since the Catholic faith holds that Mary was conceived without sin and that she led a sinless life, one may wonder why we recourse to her and how such a pure creature could sympathize with our soiled and even polluted condition. If she had nothing to be repented of, how might she lead me in my way towards contrition and then righteousness?