People, I have discovered, are layers and layers of secrets. You believe you know them, that you understand them, but their motives are always hidden from you, buried in their own hearts. You will never know them, but sometimes you decide to trust them.

This quote means that people are very complex, and often their motives and behaviors can be hard to understand. Even if you think you know someone, you can never completely know what is going on in their head or heart. You might think you understand them, but their thoughts and feelings remain secret. Even though it can be difficult, you might have to put your trust in other people and accept that you don’t truly know them.