Who is Our Lady (The Virgin Mary) from Veronika Decides to Die and what is their importance?

In the Christian tradition, particularly that of the Roman Catholic faith, the Virgin Mary, the earthly mother of Jesus Christ, is perceived and revered as a compassionate intercessor, someone whose faith and trust in God is so pure and so ideal that if she speaks on someone's behalf, God will listen. Veronika's reminiscences of a portrait of the Virgin lead to discussion between her and Eduard on how Our Lady is perceived, as well as what they believe she truly represents.