Can a daa‘iyah sit alone with a woman (khulwah) for teaching purposes?.
Praise be to Allaah.
It is not permissible for the daa‘iyah to be alone with a
woman who he is calling to Islam or teaching, because that is haraam, and
the means to obedience and worship cannot be something haraam. End quote.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him)