What does it mean

This message means:

• The person or account you are trying to send money to is not saved in your system as a regular recipient (a beneficiary).
• Because of this, you need to double-check (reconfirm) all the details of the person you are paying.
• It's a warning that once you send this payment, it cannot be canceled or reversed (recalled).

Essentially, it's asking you to be extra careful before proceeding with the payment because the details aren't pre-saved and the transaction will be final.