Is it permissible to marry a young man who insists on taking out an interest-bearing loan to buy a house, and is the questioner sinful for knowing about it?

Borrowing with usury is one of the gravest forbidden acts. However, it is not forbidden to marry someone who borrows with usury, especially if it is due to an interpretation or emulation of someone who permits it. It is permissible to marry the aforementioned young man, and there is no sin in residing in the dwelling he purchased with a usurious loan, because the prohibition in a usurious loan is related to the borrower's liability, not to the money itself. One should be keen to marry a person of faith and good character.