This is a great place. Newly renovated and very clean, it is not as "mini" as the listing suggests. For two people, it was very comfortable.
Location is ideal. About a 2 minute walk to the Cathedral and the Cloisters and to one of the main streets for the nightly Monreale passeggiata.
Marzia and her daughter and husband were very helpful. We had stopped just outside the centro for a coffee and were messaging back and forth with Marzia about where to park, etc, when suddenly she and her daughter, Paola, swooped into the pasticceria and led us directly to the apartment and then to find a parking place.
We only booked it a few hours before we arrived and communication was fast and efficient.
Monreale is a great little town with two amazing sites and you couldn't ask for a better base for exploring it than Marzia's apartment.