Is it safe as long as (a) you see them do it and (b) you make sure it shows in your Bank Transfer is by way the safest method for car sales. is just stupid, the most secure way to make almost instant transactions. banghead. Transfer money instantly and securely with SOFORT banking, Western Union's new payment option. Your. I pay using bank transfers as much as possible. You fill in a paying-in slip and get the stub as proof of payment. The seller gets instant cash.