Smoking is haraam because of evidence which we have explained previously in the answer to question no. 9083.
The one who persists in smoking is no longer regarded as being of good character, and the basic principle is that a woman should choose a husband who is righteous and of good character, who does not commit major sins or persist in minor sins, and who is not known as an evildoer. But if she is getting older and fears that no one will propose to her in the near future, and this suitor is religiously committed and of good character in other ways, such as if he prays regularly and is kind and has a good attitude, and he keeps away from evil and immoral things, after enquiring closely about him, then she may pray istikhaarah and ask Allaah for guidance, and agree to marry him, but she should advise him after that and encourage him to give up smoking.
But if she still has some time and is likely to have the opportunity to marry someone else who is righteous, then she should not accept the suitor who smokes, because of what we have stated above that he is persisting in sin, and because smoking is harmful to him and others, and it will also harm the wife and children. A woman may not be able to stand being intimate when there is the foul stench of smoke, and staying with the husband may cause her distress and hardship. May Allaah help us all to do that which He loves and which pleases Him.
And Allaah knows best.