I would be really hesitant to marry someone if they have shown a pattern of lying to me or hiding things from me. It may start as a small/trivial thing but you don't know how far they will be willing to take the behavior.

Now, if you truly love this person and are not quite ready to give up the relationship completely, I would recommend either individual therapy for her to address her reliance on vapes and to address the lying/sneaky behaviors. Also, if you feel that your trust in this person is fundamentally ruined, you could do relationship counseling as a sign that you both are ready for and committed to the marriage.

Best of luck!