I'm not clear to what you're asking but I'll try anyway. If you own a home and owe more than it's worth you can rent it for whatever amount you can get someone to pay, that is up to you. To sell a home, you must be able to clear the mortgage either with the proceeds of the sale or the proceeds plus cash out of your pocket.
If you can't cover the debt and need to sell, you can do a short sale. This process takes months and the home must be listed for sale with an agent and available for the full market. You can't sell it to a friend or relative with a pre-arrangement or you will violate the terms they will demand in order to release the title.
If you are in a rent to own scenario where the purchase price is below what is owed, you are in a bad arrangement that will likely never come together. These are typically terrible deals for the buyer and should be avoided.
If I haven't addressed your issues, please ask again and provide more information. Best of luck.