"Quel est le sens de ta vie?"
Here's a breakdown of the phrase:
* Quel - What
* est - is
* le sens - the meaning
* de - of
* ta - your
* vie - life
You can also say:
"Quel est le but de ta vie?"
This translates to "What is the purpose of your life?"
Both phrases are commonly used to ask about the meaning or purpose of someone's life.