Quite honestly,
I'd have to say that you should deal with it. I don't think she will stop, even though she said that. Also, and as an ex-smoker I know this... the smell doesn't bother them! Really! Ok, I'm not talking about no shower in four days trailer park cigar/cigarette smell, but the the odor of tobacco is not unpleasant to a smoker.
Quitting smoking (for me) was quite an experience. Even today, I still dabble with smoking a Peterson pipe (usually during stressfull times) and worry about getting 'sucked back in' to that addiction! I remember dreaming about smoking five years after I quit and waking up distressed about starting again!
There is a reason the saying exists 'you can't teach an old dog new tricks'. Old dogs can learn new tricks, but only if they want to.
Regards,
Malta