[MRM]

The obvious way is a wire transfer. These days you need to do a verbal verification on both ends - no emails - to confirm. Emails can be viewed by third parties, even if they don’t have a virus on your C drive, so never confirm wire instructions by email. Use fax if you need a paper copy. Faxes can’t be viewed or intercepted by third parties, so they’re secure for issuing wire transfer instructions.

A certified check is the second most obvious way. You send it to the bank by courier and have it deposited. As with wires, you confirm in person. Obviously your bank contacts the other bank and confirms the check is legit and the account is legal. If you do that there’s no risk to you. The bank is at risk if they make a mistake and the buyer is at risk for you not shipping, but that’s not an issue.

He could have a courier deliver cash to your office. There’s no prohibition on cash transfers. He just needs to fill out the proper paperwork.

He could have his bank write a letter of credit. Old school, but it would do what you want done.