I just want to edit my reply above, to etrips, to say that you won't convert your girl from combustion by insistence. If it happens it will be because you offered the starter kit, a couple of fabulous flavor liquids, and maybe issued a challenge/reward. Like "try vaping instead of smoking for one evening, and if you make it to bedtime, you can still have a cigarette if you still want one, and if you succeed at meeting the challenge there is a gift for you (beautiful lingerie, bottle of brandy, invitation to dinner at her favorite restaurant, or whatever will appeal)".
Show her a list of flavors. If you vape yourself, make sure the starter kit you give her will be one you'll be fine using yourself if she rejects it and doesn't like vaping at all.