How to get Hopesfire - Elder Scrolls: Morrowind
Location: Sotha Sil, Dome of Sotha Sil
Requirements: Completed all of the Tribunal Story line
Video: How to get Hopesfire and Trueflame
Hopesfire is found on the corpse of Almalexia after you kill her during the final quest of the Tribunal Expansion Pack. You find Almalexia inside of the final room of the Sotha Sil dungeon which you only gain access to once you're on the final quest in the Tribunal story.
As you can probably already assume, you'll have to do the entire Tribunal Expansion if you hope to get this weapon. Basically, it's your reward for finishing all of the quests in the Tribunal Expansion Pack. Note: Once you gain access to the High Chapel in Mournhold you can technically kill Almalexia at any point and loot this weapon from her corpse too. You don't need to wait until the final battle of the final quest. Fair warning though, the fight with Almalexia is very difficult because you must fight her plus all of her guards at the same time.