The true ending epilogue in Persona 4 Golden can be quite tricky to achieve, and requires following a specific set of steps. First and foremost, it's important to note that in order to get the true ending, you must have completed the game at least once already.
Once you have completed the game, load up your game save and continue playing until you reach December 3rd. This is a very important date, as it marks the start of a new event that is necessary for unlocking the true ending. On this date, when you wake up in the morning, your friends will come over and invite you to go to Junes with them.
When you arrive at Junes, you will be asked if you want to go inside. Instead of going inside, choose to walk around in the parking lot. This will trigger a new event where you meet a new character, who will give you a letter to deliver to Marie.
Deliver the letter to Marie and a new dungeon will unlock. This dungeon is called the Hollow Forest, and is essential for unlocking the true ending. However, in order to gain access to the final floor of the Hollow Forest, you must first max out Marie's social link. This can be achieved by spending time with her and giving her the correct gifts.
Once you've maxed out Marie's social link, head back to the Hollow Forest and make your way to the final floor. Here, you will face off against the final boss of Persona 4 Golden. Defeat him and you will unlock the true ending epilogue.
Overall, unlocking the true ending in Persona 4 Golden requires dedication and careful attention to detail. But with a bit of patience and strategy, it's definitely achievable. So keep these tips in mind and get ready to experience the full story of Persona 4 Golden!