"L'inquiétude est l'intérêt payé par ceux qui empruntent des ennuis."

Simplified Meaning:

When you worry, it’s like you're adding extra problems to your life before anything bad has even happened. Imagine you have a big test tomorrow, and you start thinking, "What if I fail?" Even though the test hasn't happened yet, you feel scared and stressed. This is like borrowing trouble, because you're creating problems in your mind that might not even occur. Worrying too much is like making a small issue feel much bigger. Just like when you borrow money from someone and have to pay back more because of interest, worrying makes your problems seem worse than they are. For example, if you keep thinking, "What if it rains during my picnic?" you might not enjoy the beautiful weather you're having now. Instead of worrying about things that may never happen, focus on what you can do right now. Study for your test, or plan for the picnic but have a backup plan in case it rains. This way, you reduce stress and enjoy life more. By not borrowing trouble, you pay less interest in the form of unnecessary worry.