Realtor,
In negotiation terms, your potential buyer is worried that other alternatives would have met their needs better (either in terms of the home or the value). They're concerned about having "buyer's remorse."
Some people will never get over this. However, it should be your job to minimize those experiencing this AND, for those who do, the effects (especially since if they have buyer's remorse and if they do find a home that would have made them happier, you lose future sales and referrals!).
Here's what I'd do: first and foremost, follow the advice from the other contributors here - make sure you understand your prospective buyer's needs and try to help them prioritize them - what are their must haves? What are their "nice to haves", etc.
THEN, don't just show them the houses you want to show them, print out listings for the range in the market - all the houses that might meet their needs. You can go further to print out what's sold in their range for the last six months (emails better - save some trees
). Give them as wide a view of the market, what's out there and for what prices as you can. The more educated they feel about the market and the more knowledge they have about what's out there, the more confident they'll be making a decision.
Keep in mind that your goal shouldn't be to make a sale in the few days they have - if you rush them, they'll feel the pressure and it will give them cold feet. Give them time. Let them look around. If the home you've shown them is the right one, they'll figure it out. If it's not, it doesn't benefit you or them to sell it to them (in the long run).
Always remember - your goal shouldn't be "making a sale." It should be helping your customers - if you do that, the sale (and many more to follow) will come naturally.
Good luck.
Stephen