If your house has been on the market for a while, you need to move quickly, or you have a motivated buyer who can't gather enough cash to buy but can put down a non-refundable deposit on a future buy, you might consider a Lease-to-Buy Option.
Your Realtor (or your collection of real estate books) can walk you through the details, but the overall picture is this: You and your
agree to a set price (great for the
/buyer if the market goes up and great for you if the market goes down) and time frame to make an offer with a non-refundable "earnest money" deposit (often called a "consideration" in lease-buy options) from your
may offer to buy at any time during your term, often putting their rent and earnest money against the agreed-upon price. If they decide not to buy, you keep the earnest money and put the house on the market again (you hope at a higher price than the year before), continue your lease-to-buy, or simply switch to a standard rental agreement with your tenant.