The KJV and the NASB are significantly different here. The Hebrew words are the same but the way they are put together comes out different. The translations I have to compare show the same two tracks. Most agree with the NASB.
(Proverbs 21:8 NAS77) The way of a guilty man is crooked, But as for the pure, his conduct is upright.The King James does not hold together as logical literature. The first part seems to be a statement about original sin and depravity. If that is the correct translation then the second part is impossible. You cannot have the nature of man “froward” (crooked NASB) (2019) and “pure” (2134) at the same time. That is why I would go with the NASB on this.
That makes it a statement consistent with the idea of knowing a tree by its fruit. Our lives demonstrate the condition of our souls.
So? Don’t judge yourself on one bad day but on the pattern and trends you see behind you. Look at the goals and dreams ahead. Are they crooked or upright? What are you going to do about it?