There is a lot of things The Princess Guide tells you and a number of things you have to just figure out. Among the most confusing is how to unlock the various endings. Every character has an okay, good and best ending, which are not quite night and day, but do change a number of things. However, given the amount of things going on, choice system and more, figuring out the requirements can seem much harder than it actually is.
How to unlock the various endings
The ending you unlock is determined by how much faith your princess has. It doesn’t matter how often you praise of scold her, what you use your points on, whether or not you bothered with side missions, just what level her faith is at. While I don’t have the exact numbers, it should be a score of one or two will unlock the okay ending, three and four is good and maxing out gives you the best ending.
How to unlock them all quickly
The fastest way to see every ending is to rush to the end, beat the game and then focus on leveling faith. This can be done by going into the training menu, selecting bonus tasks that you know you can quickly accomplish and give faith. Once you get her to level like four, beat the game again and get the good ending. Repeat this process to unlock the good ending and repeat it for each princess.
While this might seem a little lackluster, make sure to actually pay attention to every ending. They might seem eerily similar, though I can assure you any ending you actually unlock will eventually have different dialogue. Less so for the two lower tier endings, with the best ending being a massive departure at the end.