The word behind "goodness" is chesed, footnoted in the NKJV as* mercy, *the same covenant word 19:22 turned on.
Quick answer
Everyone advertises their own loyalty. Very few can be counted on, and the verse says the gap between those two facts is the problem.
Read both lines
The verb in the first line is about proclaiming, announcing, saying it out loud, so the picture is of a man telling you how loyal he is. That the word he uses about himself is chesed, the covenant term for steadfast love, makes the claim enormous and the ease of making it absurd. Then the second line asks a question the verse declines to answer, and the form is the argument: if faithful men were common, finding one would not be a question. Chapter 19 said what is desirable in a person is his chesed. This one adds that everybody already knows that, which is precisely why everybody claims it.
Related: Proverbs 19:22 · Proverbs 25:14 · Proverbs 27:2
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.