What is the ruling on a committed woman, who wears the legal hijab, studying in a mixed institute in European countries, for the purpose of learning the language and then completing a master's degree, given the necessity of the language for communication and da'wah (inviting to Islam)?

Scholars have issued fatwas prohibiting mixing [of genders] in education and other spheres due to the corrupting influences and dangers that result from it. Therefore, it is not permissible for a Muslim student to study in mixed classes because of the great temptation involved. Moreover, a woman's education in schools and universities is not among the necessities that would permit forbidden acts. Language can be learned through homeschooling, or audio and video tapes and books, or by enrolling in a university or institute and taking exams by correspondence or with the presence of the husband.