I assume you are the seller. An agent will likely ask you to sign a one or two day agreement saying that you agree to pay her company a commission if her buyer does buy the house. There will be more details like the buyers name, the commission amount and a term period that it will occur. Pretty simple really. The added advantage to you is you will have an experienced agent working the buyers side and probably helping out on on your side to be sure the deal goes through. it is a win-win for you really since any buyer you would find will want a deep discount on the sales price because they know you have no agents involved and they will want to share the savings.
You already have two great answers to your question and I agree completely. Best of bold worlds for you. I just had a disturbing item show up on a title search - a $23,000 lien on the person buying my listing and we're scheduled to close on Friday. Would you know how to handle that or any other issues that could arise?
The experienced agent will know how to get over the humps that almost always arise between acceptance of an offer and closing.