Ruling on sitting with one's brother's wife

Question:
One of the listening brothers asks: Is it permissible for me to sit with my brother's wife when we are alone in the residence?

Answer:
It is not permissible for you to do that. It is not permissible for you to be alone with a woman, especially your brother's wife. There must be a third person with you two, such as your mother, or your sister, or a maid, or something similar to those who make it a group of three other than you. This is based on the saying of the Prophet (peace and blessings be upon him): If there is a fourth person with you two, Satan does not become the third. So there is no harm in you sitting with your brother's wife while your mother is with you, or your sisters are with you, provided she observes hijab and stays away from the causes of fitnah.
Likewise, your cousin's daughter, your maternal aunt, and the like. And likewise, the presence of a woman from the neighbors in the house, and you speaking with her and her speaking with you regarding matters concerning the neighbors, or greetings and salutations, or something similar to that, in a manner that contains no suspicion or doubt. Yes.

The presenter : May Allah reward you with good.