I would tell them you will pay them a premium and handle all maintenance during that time to sweeten the pot for them!

In that case, there is not a lot that you can do besides 1) sweeten the deal for them, and 2) in lieu of a track record, keep track of some of these deals that you have done and show how you were right in predicting the outcome (maybe the sale price) when they are done.

Can you sweeten the deal by proving you are a solid buyer who will close quickly? 

The other ideas, sweetening your offer with a flexible closing date, offering more to simply lock the deal before it turns into multiple offer, etc are also good. 

Keeping your deal is the key, since many will try to take half or more of your deal.You need to make it easy for the lender to get his money back and sweeten the deal.

. - One way to sweeten the terms is get some of your own money in the deal.

I have no doubt that it "sweetened" my proposal.

Should I sweeten the deal a little?

If you need $3500 and you don't think another business person would pay that, try sweetening the pot by signing him on a lease option $3500/mo with a $500/mo credit if he decides to buy after a year or two??

Try Sweeten CPA.