When I receive a MT 103 does it mean the other party have received my payment?

No, receiving an MT 103 does not necessarily mean the other party has received your payment. The MT 103 is a standardized message used in the SWIFT network to confirm that a payment instruction has been sent, but it only indicates that the payment has been processed by the sending bank. The actual credit to the recipient's account may take additional time, depending on the banks involved and the processing times.