what is the most secure way to transfer money?

The safest way to tranfer money is a wire transfer from one bank to another. Given the security precations of the banks involved this method is nearly foolproof. If one party or the other does not have access to a bank. Then your best bet is Western Union for a quick transfer or a postal money order for a non-emergency situation. Also a postal money order will be much cheaper than Western Union.

In general, if you are transferring money over the internet, you need to use a well-known secure site such as Western Union, PayPal or your own bank's website. You can also do a wire transfer by going in person to a financial institution such as your own bank branch and requesting they send it for you.