salamou3alaikoum, im married to christian women, and she want to bay a hous throught a bank lone, i told her that i cant do that since im a muslim. but she suggest that she will bay the hous with alone from the bank , and she will sel me the half of it without any rent, that meens that , we make a contract betwin me and her that says exactely how much i should pay for my half. is that ok in islam ? im sorry for my english mistakes.
wasalamou3alaykoum.

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

Dealing with Riba (interest and/or usury) is forbidden for Muslims and for non-Muslims and Allaah stated in the Quran that He forbade Riba for the People of the Book before us; for more benefit, please refer to Fataawa 86701 and 85569.

Therefore, you should forbid your Christian wife from borrowing money with Riba. If accepting her suggestion which you mentioned in the question is the reason for her borrowing money, then it is not permissible for you to accept this suggestion as this leads to helping in sin and causing it.

Allaah Knows best.