Good question. The reason why the landlord may rejected your friend's application for renting a unit will probably never be able to be discovered by you or him.Many times a landlord faced with many applicants will simply choose the one that looks the most stable financially with a stable job history. The landlord wants to make sure the rent is paid on time and the rental not damaged. The landlord has no obligation to set forth the reasons why an applicant to rent a unit was rejected.