His friends might feel betrayed. They would be mourning his death while he was actually alive. This could lead to a lot of anger and mistrust when they find out the truth.
The village he loves so much could be in chaos. Without Naruto, the symbol of hope and strength, the villagers might lose their morale. There could be power struggles as well, since Naruto was a major stabilizer in the political and social structure of the village. Also, his enemies might think they've won and become overconfident, which could actually work in Naruto's favor when he finally reveals himself, but in the short - term it could be a dangerous situation.
One consequence could be that his friends are devastated at first. They might go through a period of grief and self - blame for not being able to protect him.
Well, Naruto could have made a deal with some powerful being or used some sort of forbidden technique. Maybe he found a way to transfer his life signs to another object or being, making it seem like he was dead. He's always been resourceful and full of surprises, so faking his own death in a really elaborate and unexpected way is not out of the question.
The Death Eaters might think they've won at first. There could be chaos and fear among the good wizards. But it could also lead to a secret resistance growing stronger.
One possible plotline could be that Naruto fakes his death to protect the village from a powerful enemy who has a vendetta against him specifically. He might do this to draw the enemy out and expose their weaknesses.
A secret organization that has been operating in the shadows and views Naruto as a major threat to their plans. They might be planning something big like taking over the ninja world, and Naruto's presence and influence stand in their way. So, Naruto fakes his death to gather intelligence on this organization without alerting them.
Sakura would be extremely angry at first. She has known Naruto for a long time and would feel betrayed that he didn't trust her enough to tell the truth. But later, she would understand his reasons and might even help him if she could.
One possibility is that Harry uses some advanced and little - known magic. He could have found a spell in an ancient book in the Room of Requirement. This spell might allow him to project an image of his death while he actually hides himself in a magically protected space. He may also have made arrangements with the Order of the Phoenix to spread the news of his death convincingly.
One possible reason could be to protect his family. After the war, Naruto might have made many enemies. By faking his death, he could draw the attention of these enemies away from his family, especially his wife and children. His enemies would think he's no longer a threat and stop targeting his loved ones.
One possible plot development could be that Naruto fakes his death to outwit a powerful enemy. He might go into hiding, secretly gathering information and allies to strike back at the right moment.
Well, he might use some substitution jutsu. He could replace himself with a log or something similar at the crucial moment, making it seem like he's been killed.