This item can be found off of any of the second tier prisoners.
In PoJ, there are several tiers of mobs. The first tier are the prisoners, roaming sentries, and rats found in the rectangular hallway with cells that you encounter when you first enter from the graveyard (and also where the exit can be found). These mobs drop some vendor junk items, and the rats drop a quest note. Drops here are around 10-20% of kills.
From this section, there is a hallway that leads to the second tier of mobs. Second tier mobs are simply tougher prisoners, sentries, and rats.
>>The prisoners in this section (second tier) are the ones that drop the Golden Charm of the Hopeful!<<
It is a random drop from any of the prisoners (regardless of faction) in this area. They can also drop a pally shield, a chain-class bracer, and a warrior 1HB weapon, along with various vendor trash. You will get an item to drop about 10-20% of the time.
Some notes about the first and second tier:
-Players 54 and below will agro the wandering rats, and even some nearby prisoners, so be careful when pulling
-Players 54 and below under the cloak of an illusion (wolf, bear, etc) will draw agro even if they aren't fighting
-Pets that are 54 and below will draw agro if other mobs see them engage in combat
-The prisoners in the second tier are on zone-specific faction; killing them will have an impact on other mobs in the area