Assalam-o-alikum,
There are many students who go abroad for studies and there they have to stay for many years for their education. Mostly the countries are european or other western countries and it's very common in such countries to have girlfriends, boyfriends and such relations go till the last extent (sex). When you are living in such environment it pushes you a bit towards their culture. Is it allowed to marry a christian girl even when you know that she will not leave her country when you complete your studies and will not go with you to your country and if we don't get marry we fear of fitnah. What does islam says in such matters?

All perfect praise be to Allah, The Lord of the Worlds. I testify that none is worthy of worship except Allah and that Muhammad, is His slave and messenger.

First of all, we say that it is permissible to marry a non-Muslim woman from the People of the Book (Christians and Jews) provided that she is chaste, as stated in the verse where Allah The Exalted Says (what means): {This day [all] good foods have been made lawful, and the food of those who were given the Scripture is lawful for you and your food is lawful for them. And [lawful in marriage are] chaste women from among the believers and chaste women from among those who were given the Scripture before you …} [Quran 5:5]

What you find problematic is not clear to us. If you mean having children with her then divorcing her and fearing for your children’s religiosity, then you should know that the scholars of Fiqh (jurisprudence) stated that one of the legitimate excuses warranting the prevention of pregnancy is the fear for the religiosity of the children. Al-Mawsoo‘ah Al-Fiqhiyyah (The Encyclopedia of Fiqh) reads: “Among the legitimate excuses for practicing coitus interruptus are the following: … when corruption prevails and he fears that his offspring would be corrupted.” [End of quote]

Accordingly, it is allowable to resort to coitus interruptus in this situation to avoid having children with her. Nevertheless, it is better for the Muslim man to marry a Muslim woman who would help him adhere to Islam and foster his children’s religiosity, if they are blessed with any.

Note that marriage with the intention of divorce is permitted according to the view of the majority of the jurists on the condition that there is no prior agreement between the two parties on divorce after a specific period of time. If there is such a prior agreement, then the marriage is prohibited according to the consensus of the scholars, and the contract is invalid.

Also note that it is better for the Muslim to study in a Muslim country to spare himself such inconvenience. Residing in a non-Muslim country poses many risks to the Muslim’s religiosity and morality given the differences in ideology and culture.

For more benefit, please refer to Fatwa 92602.

Allah knows best.