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