When it comes to telling the truth, or knowing the truth, there is plenty of untruths being spoken. We would like to believe that people under oath will, in fact, tell the troof, the whole troof an nuthin buts the troof.
The truth is, we really want truth that sits well with us, that agrees with us, that requires little if any change from us. People we look for to tell us the truth, often do not. If they did, we likely would stop trusting in them.