APOLOGY TO LANDLORD FOR LATE RENT PAYMENT: WITH EXPLANATION
Enclosed is my rent check for [MONTH, ex. September].
I do understand this payment is late and I hope you will accept my apology. [BRIEFLY STATE REASON, ex. I was forced to take a late salary payment this month to slow business.] [MAKE REASSURING STATEMENT, ex. I am assured, nonetheless, that there should be no similar problems in the future.] You have my guarantee that this will not occur again.