How do you know what to believe?  It is not only that you cannot trust what you read or hear.  You cannot trust the human brain.  It looks for data that matches its beliefs.  That is how it operates.  Are you aware of this?  It will deny and block out anything that does not fit.  Do you like puzzles?  That is what the brain does:  seeks those pieces that fit right into place.  So, how to know truth?  See how the brain operates and rise above it.  Refuse to wear the blinders, no matter how good it feels, and try on various lenses before making decisions and statements that lock you into one way of doing and seeing things.  It can be quite eye-opening to remove the blinders … quite heart-expanding.  You may still go back to your beliefs, but perhaps with a bit more compassion.  You are so very loved.