Aside from paypal, money order is the only other type of payment I accept. It's basically like getting cash because in order to get one, your buyer has to pay for it in cash. Think of it as a voucher for that amount of cash. There's no risk to you if you choose to accept a money order because although you deposit it as you would a check, it clears the moment it's deposited. That's why a lot of government agencies and apartment complexes will accept money orders and not personal checks. It's basically an assurance that the buyer already has the funds so they don't have to worry about checks bouncing or payment failing to clear.
The only downside to money order is that the whole transaction takes a bit longer because it has to be mailed. And as always, wait until you receive the payment to ship on your end so she can't try and tell you that she sent it but it got "lost" in the mail.