"The greatest thing in the world is to know how to belong to oneself."

Montaigne is pointing to a quiet kind of freedom: being at home with yourself. To “belong to oneself” means you’re not constantly handing your peace, worth, or direction over to other people’s opinions, expectations, or moods. It’s knowing what you value, what you need, and what feels true for you, even when the world is loud.
In real life, this might look like saying no without guilt, spending time alone without feeling empty, or choosing a path that makes sense to you even if it doesn’t impress everyone else. It’s not about being selfish or detached. It’s about having an inner place to return to, a steady sense that your life is yours to inhabit fully.