1) Is the home that is being sold a short sale or standard sale?
2) If the house that is being sold is a Short Sale, than I would ask a couple of more questions:
a) Are the owners still looking to do a short sale on the home? If the answer if Yes, than you might want to negotiate a reduced rent on the home. Maybe only offer to pay for half a months rents. You could get a very good deal on the monthly rental if a short sale, but you need to be prepared to move in about 3 to 4 months.
If the answers you are given by the listing agent does not sit well with you, I would suggest looking for another rental home. If the listing agent's landlord is paying a commission to rent the home, get a licensed Realtor to help you with the paperwork (It does not cost you anything), the landlord sometimes is willing to pay a commission to the renter's agent.
Best of luck!