Want to sell house to renters without rent to own structure

[Bill Coleman]

I have a house I am attempting to sell to an FHA approved buyer. Trouble is that the appraiser did a poor job of valuing the house and now the buyers can't buy it. The house was listed at the upper limit of its value but in the super hot Denver market, it's still within reason.

These buyers need a place to live and will rent it instead of buying it. 

I would like to eventually sell it to them once they have enough down payment and use the eventual sale to them as an incentive to pay their rent and keep the place in good shape. 

Can anyone offer a rental structure that would achieve this?

I looked at the threads on lease to own and right of first refusal and all of those options seem very complicated and could open me to risk. I could easily just hold onto it and rent it without all the complication.