To understand it better, let's use parallelism to show that this example has the same level of importance.
Basically the wife hated
If the husband stop drinking & gambling but continue smoking, can he justify his belief that he's in love?
James 2:10 For whoever shall keep the whole law, and yet stumble in one point, he is guilty of all.
James 3: 2 For we all stumble in many things. If anyone does not stumble in word, he is a perfect man, able also to bridle the whole body.
Blessed is he who keeps the words of this prophecy.
Revelation 1:3 Blessed is he who reads and those who hear the words of this prophecy, and keep those things which are written in it; for the time is near.
This is how I justify my belief.