Umm Qirfah al-Fazariyyah is Fatimah bint Rabi`ah ibn Badr. Her story has become widely known among the enemies of Islam, and they have started to use it to attack Islam and accuse it of being violent and cruel.
The chains of narrators of this story are all weak and are not sound, and what is mentioned in this story about her being mutilated and torn in two is very odd and weird. Hence it is not permissible to mention this story, except by way of warning against it.