Day 4: The Mirror of Her Dreams by Stephen R. Donaldson
Also, I guess, its sequel: A Man Rides Through. Fantasy. A woman from an affluent family drifts through life unnoticed and unwanted by anyone. An inept mage is tasked with finding the saviour of Mordant, but nobody thinks he can do it. He ends up in her NYC apartment, but is it an accident? Political intrigue, finding one's value when no-one else sees it, magic and of course some romance.
*Note: I tried to read it again recently and am struggling a bit but I suspect that's more my current headspace than the book itself.