One has to examine the very concept: What do we mean by "truth"?

To my mind, the words "true" or "truth" refer to a direct correspondence between a stated concept and reality. "It is raining outside." To this to be true, if we go outside we must find moisture descending.

This is fine, for a simple statement of a physical, checkable fact.

But what about statements of impressions, opinions, perceptions? Take
"I love you." This seems a statement of a yes/no "fact", but its truth is not checkable--even by the speaker! Why not? Because "love" doesn't refer to only one thing. The panting, testosterone poisoned teenage lover urgently whispers in her ear that he loves her, and to his mind he may (or may not) be telling the truth, but otherwise considered "the truth" may be that he's not in love, but in lust. In other words, maybe it's true but not the truth, so to speak.

Or "She's a beautiful girl." The above youth will enthusiastically agree, but what's the meaning of "beautiful"? Assuming that he's sincere, he's telling the truth as to his reaction to her charms, but the concept is so slippery that many would disagree, and say, "Oh, she's attractive, but not 'beautiful'."

Suppose the used car salesman tells you, "This car has only 62,000 miles on it." He may be lying through his teeth, knowingly. Or he may think he's telling the truth, but in fact it's 90,000 miles and someone has rolled back the odometer, in which case he's telling "the truth", but it's not true.

If the salesman tells you, "This would be a good choice of a car for you to buy," you have both the subjective truth/falsity of his statement to consider and also the reality (maybe he doesn't know the mechanical condition of the car, or maybe he doesn't know the customer's needs or ability to pay) of the statement of the customer fit.

There are statements which are impossible of verification or refutation.

Dave Oesterreich