The vessel will be repaired according to MSC Cruises. Since the interiors are intact, they'll do a Star Princess on her and repair the area. Also the area of the fire corresponds to the part that was added to her during her November 2015 lengthening, so most of the fire was on the part that was added during her lengthening.
Even if that area was burned beyond repair, they could scrap only the extension and keep the remaining parts and reconnect them. Granted it would restore her back to her pre-2015 length, but they can always add a new extension to her later on.