The French phrase "C'est la vie" means "That's life" - "That's the way life is".
In English, the word "vie" means "to strive, to struggle, to compete, to battle".
In life, we have to fight hard for what we want. We have to strive, struggle, battle, compete to achieve.
Because just sitting, and wishing, and hoping, isn't going to make our dream come true.
We have to fight for it. We have to battle for it.
That's life. A training ground. A hard school, sometimes. To teach us to become better, stronger.
That's why "C'est la vie" = Vie = Strive
