Here's a breakdown:
* vous: You (plural, formal)
* ne: not
* fiez: trust (second person plural, present tense of "fier")
* jamais: never
* la personne: the person
* aveuglement: blindly
This phrase warns against the danger of placing absolute trust in someone without any critical evaluation or consideration. It emphasizes the importance of being cautious and discerning in your interactions with others, rather than being overly trusting.