Also, be sure to check the consequences if they can't go through with the guarantee. It may be just some dollar amount back to you at closing. As Don suggested, read the fine print. At the end of the day, you want the house sold. And that is best done by a qualified, motivated real estate agent. So that should be the first consideration when selecting an agent.

A 30 day guarantee to sell a property? Sure, an agent could offer it. But could the agent deliver? You can't even close on most properties in 30 days.

I've heard of agents who've offered 90 day guarantees, and some of them have gotten burned. But on top of that, there are a lot of conditions attached to it. For example, the property has to be listed at or below where the agent suggests. And often there's a built-in de-escalator clause which the seller must comply with. And, further, there might be a base price which you must agree to accept.

For example, suppose most agents suggest you list your home at $400,000, and say that you probably will get an offer within 90 days at $385,000 or higher. In the case of a guarantee, an agent might require that you list at $385,000 and agree to a $10,000 price reduction every 30 days. After 30 days, the price drops to $375,000. After 60 days, it drops to $365,000. So it'll be on the market for the final 30 days of the guarantee (if you haven't gotten a contract earlier) for $365,000 when other similar properties are listed for $400,000. And you might get an offer for, say, $355,000. Maybe your agreement requires that you accept any offer above $354,000 to enforce the guarantee. So you sell at $355,000. And that might be fine with you. On the other hand, with another agent, and maybe waiting a bit longer (or maybe not), you might have been able to sell at $380,000 or $390,000.

So you really have to look into a guarantee's fine print.