What is the ruling on buying a house in a non-Islamic country through a bank with installments over 15 years, due to its high price and the impossibility of purchasing it with cash?

If the bank lends an amount to be repaid in monthly or annual installments with an increase, this is forbidden usury (riba) and is not permissible except in cases of necessity. However, if the bank buys the house and sells it to you for more than its price, there is no harm, provided that the house enters into the bank's possession and responsibility before selling it to you. Merely paying the price on your behalf is not a sale, but rather a forbidden usurious loan. There are Islamic companies in the West that engage in financing transactions, such as buying real estate, and one can search for them. It is advisable to consult the Assembly of Muslim Jurists of America in one's country.