As I've mentioned before, it is in humanity's best interest to pursue truth. Resort to whatever etiology you want as to why, you still gotta be able to sift through the input you receive and decide what works, what doesn't. What's gonna play out in the long run (because it's true) and what's gonna peter out and let you down.
People from all walks of life delight in their inherent ability to tell whether or not someone's lying. This is good, this is essential. But! Unless someone truly knows Jesus—who is Truth (see John 14:6)—then the whole paradigm will be askew. There are several levels of truth. The simple statement of "two plus two equals four" is solid. Truth (more of a fact, a law really). But when dealing with human beings who have a boundless capacity for deceit, facts and laws and rules mean nothing. And I think we know that. There's an unpredictability that makes interaction with strangers a gamble at best, the mistake of your life at worst. If we don't know how to tell truth from lies—not just facts and figures from their opposites—then we'll be taken advantage of, strip-mined (think "remora") and quite possibly unable to fulfill our calling before the Lord. That's disastrous. And scary when you realize how many people in society care nothing about honest interaction and transparency of motive.
1. "For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart" (Hebrews 4:12, emphasis mine)
2. "Every word of God is pure: He is a shield unto them that put their trust in Him" (Proverbs 30:5)
Tomes could be written on the first verse, I'm sure many have. The verse itself refers to the Bible, the Word of God. The Hebrews verse calls it a sword. With the second verse, we see that God is our shield. His word, our sword. God Himself, our shield (see also Psalm 84:11). Remember this. Now turn over to Matthew's gospel (10:16, emphasis mine). Jesus says "Behold, I send you forth as sheep (pretty harmless, right?) in the midst of wolves: be ye therefore wise as serpents, and harmless as doves."
Jesus is telling us here to know the tricks people use. To know them inside and out. "For we are not ignorant of [Satan's] devices." (2 Corinthians 2:11) But! He's also saying that in no way do we use them in our defense. That's God's job. This is the first step to becoming wise to the ways of the world. The first step to cultivating perspicacity—discernment.
"See that none render evil for evil unto any man; but ever follow that which is good, both among yourselves, and to all men." (1 Thessalonians 5:15)
"But whoso looketh into the perfect law of liberty, and continueth therein, he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his (and her) deed." (James 1:25, emphasis mine)
God's word is also a mirror. It shows us who we are and who we were. All of the mistakes and foibles of our old nature are laid bare. Sure the word convicts and cuts, (it tells me I'm going to hell without Jesus, for God's sake) but it also heals and informs and inspires. The way to know truth is to know God through His word. This is how we align our sense of what truth is (what feels accurate) with the highest to which we can aspire: namely Jesus. Because if you knew that everyone was lying to you (as actually happens, some days), without forgiveness, how would you be able to live in society? The two go hand in hand. Sheep? Wolf. Sword/Shield. Serpent/Dove. Discernment. Forgiveness.
Without forgiveness, the motive of which desires that the dishonest individual come to repentance and Jesus, we delight in our innate capacity for perspicacity which only ends in self-gratification and does nothing to help the other person. It's simply selfish.
Look for the thread of Truth in your Bible. The gems of discernment hidden in Psalms, Proverbs and Ecclesiastes. Study out Job's response to his "friends" (who certainly didn't have his best interests at heart). See how Joseph responded to his brothers who sold him into slavery and then lied about it. Ask with an exasperated Pontius Pilate "What is truth?" (John 18:38) The answers you'll find may surprise you. And you just may gain a greater love and appreciation for others as you learn to forgive yourself. It isn't about reigniting your faith in humanity. That's a lost cause. It's about seeing Jesus and truly knowing what He can do for a person. He will make us authentic.
"Go and do thou likewise" (Luke 10:37)