The House Saphir - Marissa Meyer

Mallory Fontaine is a fraud. Though she comes from a long line of witches, the only magic she possesses is the ability to see ghosts. She and her sister are eking out a paltry living by selling bogus spells to gullible buyers and conducting tours of an infamous mansion where Count Bastien Saphir brutally killed three of his wives more than a century ago.