Is it forbidden to provide tutoring to adult girls to encourage them to attend co-educational schools, and what is the ruling on the money earned from that? And will one who acts upon a fatwa that permits this, while doubting its correctness, be held accountable, citing the hadith: "Leave that which makes you doubt for that which does not make you doubt"?

It is permissible to teach adult girls what benefits them in their religion and worldly life, with the intention of doing good and educating the ignorant. The female teacher will be rewarded for this, and she must exert effort in guiding the students and instilling purity, chastity, and love of religion in their hearts. The money earned is lawful even if the students do not adhere to Islamic guidelines, because it is not considered an encouragement to haram. What is forbidden as a preventative measure (sadd al-dhari'ah) is permissible out of necessity and for an overriding benefit. Knowledge and education are essential, and if a shaykh from among the people of knowledge and piety issues a fatwa, his fatwa should be relied upon.