Usually when a man is giving dawah another part of his body is giving dawah other than his head! We have to be careful we need to check why are we talking to the women.
Cast your glance away and give her a phone number or direct her towards a place where Muslim sisters gather. Or if you want to give dawah invite her to a gathering where there is proper ways of giving dawah.
When a woman is talking to a man she is usually single and one side is learning about Islam, the other side is fantasizing about a relationship, the same goes for men.
Save yourselves from this hypocrisy and the fitnah. Women should give dawah to women and men should give dawah to the men.