This verse is loaded with figurative translations that take away the edge. First of all we see that “certainty” (7189b) is literally the word “truth.” It is not the same word for “truth” (571) used two other times in the KJV. The KJV is closer to being literal here. The NASB uses “correctly” (571) as a synonym for “truth.”
The first one emphasizes the idea of balanced truth. The second has the concept of reliability and stability. One might be experience, the other absolute.
If I had to do a Pumice Pathetic Paraphrase it might go,
(Proverbs 22:21 PPP) To force you to acknowledge the truth of the words of truth so you can answer with truth.So? Our lives are based in truth not opinion, fashion or consensus. You cannot be set free until you know the truth. Read, study, think, pray, listen.