"To reveal the truth" means to make something known or show what is really happening. It involves uncovering or sharing factual information or exposing the reality of a situation. Full definition
The tension we feel about social media reveals the truth about our hearts: We know it isn't about us, and it was never meant to be. (relevantmagazine.com)
-- that reveal the truth behind what y ’ all think of each other. (theeverygirl.com)
A strong data set reveals truths in cold, hard numbers. (visualnews.com)