Quitting smoking is much much more than just a nicotine habit which is why no NRT's worked for me like
vaping did, there's tonnes of habits that go along with it, hand to face motion, going out for a smoke when you have anxiety in certain situations, ritualism, bedtime smoke, after dinner smoke, craving a smoke when you smell someone else doing it, stress relief, the social aspect of it and even as simple as something like liking blowing O's.
90% of my friends all smoke, ALL of my wife's family smokes, without
vaping I don't think I would have EVER been able to quit, like people say it's more addictive than ...... and that's just not the nicotine, they actually add stuff to the tobacco in cigs that makes nicotine more addictive they also add stuff to the tobacco that makes it so you don't cough as much to mask symptoms of things like ohhh lung cancer >.>
Just ask her if she's been thinking of having a cig, tell her to be honest and you're not there to judge, if she is just get her a ego or give her an old setup with 1.5/3 mg juice and tell her to use it only if she's really thinking of having a smoke..
Hope this helps
Here's a link to a study on the additives
Pharmacological and Chemical Effects of Cigarette Additives