It doesn't guarantee it but it's the best you're going to get for that level of convenience. Basically, you initiate the transfer -> buyer accepts -> buyer wires money to Escrow -> Escrow verifies the money has been received -> seller transfer the domain -> buyer confirms and has a set number of days to review the product, the number of days is set by the seller at the beginning of the transfer -> the buyer then confirms the domain has been received -> Escrow releases the money.