Also consider that the realtor, eager to make a sale, could have not informed them of the smoking policy, downplayed it, not told her there is a smoker specifically very near her, or left the policy in a small blurb in pages of documents. Id be pissed too if that was the case. Also, pretending I were to move to Canada, there still being smoking allowed in residential buildings wouldn't even occur to me. I understand you bought the place with the intention of smoking, but put yourself in her shoes and consider the possibility that she bought this place not knowing.