In "classic" Baldur's Gate, the quest A Rogue Ogre is commonly referred to as Unshey's Belt or Unshey's Girdle of Piercing. You receive this quest from Unshey herself, simply by speaking to her, on the second floor of The Friendly Arm. With a Charisma score of 10-12, you need a reputation of at least 7 to receive this quest. Otherwise, some combination of higher Charisma, higher Reputation and/or a Friends spell will be required. Unshey even tried offering the ogre a signed copy of her new book, History of Tethyr, but unfortunately the ogre only wanted her belt.