The only one I can think of is by having trusted parties managing the money, thus when a trusted party confirms the money has been sent, you can be sure you'll receive a payment.
MY-BIT-COIN-DOT-COM
Um, he said 'trusted'.
Why don't you trust MyBitcoin? I have used them for a while and they've been fine, most of my BTC is also held by them. They also offer a great payment gateway for merchants.
Because they never returned a 10 btc over payment. It either went to the merchant, or it went to mybitcoin.com... both are claiming it went to the other. I'm inclined to believe the merchant.
In addition, it took more than 3 weeks to even get back a response from mybitcoin.com to tell me they weren't going to help.