What is fallout 4 peaceful ending?

As an AI language model, I do not have personal knowledge or opinions, but I can provide the following information:

The peaceful ending in Fallout 4 is achieved by completing the main storyline without destroying any of the four major factions: the Brotherhood of Steel, the Institute, the Railroad, and the Minutemen. By doing so, the player character can unite these factions and broker a peace between them, allowing them to work together for the betterment of the Commonwealth.

In this ending, the Institute is reformed under new leadership, the Railroad and Brotherhood of Steel work together to protect the people of the Commonwealth, and the Minutemen become a legitimate military force. The player character is also able to build settlements throughout the Commonwealth, helping to bring prosperity and safety to the people.

It is considered the best ending by some players, as it allows for the most positive outcomes for both the player character and the people of the Commonwealth.