Quick answer
Straight walking tends to come through; crookedness collapses without warning. The verse contrasts two gaits and two endings.
Read both lines
The NKJV footnotes "saved" as delivered, which is the register: rescue from trouble rather than salvation in the theological sense, and reading it the other way would put this book in the business of teaching justification, which it never does.
The second line's force is in suddenly. The crooked man's fall is not presented as gradual decline but as a single moment, which fits the picture: a man walking a twisted path is fine until the turn he does not see. The verse says nothing about how long either road runs, and that silence is characteristic. It describes the shape of two ways of going, not a timetable.
Related: Proverbs 10:9 · Proverbs 28:6 · Proverbs 28:10 · Proverbs 29:1
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.