Maggy's Faith is a trinket.
- The eternal heart is added directly to Isaac's heart containers, as opposed to appearing as a pickup.
- When held as ???, an eternal heart will spawn each floor. Upon completing each floor with one, ??? will receive a full soul heart.
- The effect will also be triggered when the floor is reset (for example, with Forget Me NowWhen activated, the level ends and is freshly regenerated with new rooms, monsters, and items. Disappears after use.).
- Since the Eternal Heart is added at the beginning of the next floor, moving from one floor to the next with an Eternal Heart looted elsewhere will give you the additional heart container plus another Eternal Heart when the next floor starts.
- If held when playing as Keeper, blue flies will not be spawned instead of the eternal heart. This is because the Eternal Heart given by Maggy's Faith is directly added to Isaac's health, and not spawned as a pickup on the ground.
- Maggy's Faith is most likely a reference to Mary Magdalene's faith in Jesus. Mary was said to be one Jesus trusted most and she stayed with him past the abandonment of his disciples, as well as being the first person he showed himself to after his resurrection.
- "Faith's reward" may constitute a subversion of the adage "Faith is its own reward", although use of the word 'faith' in the game is conflicted, as it also used in the quote for the trinket "Rosary Bead", in reference to Angel Rooms.