Would you please weigh this letter to see what the postage is?
Do you want to send it by ordinary or registered mail?
By ordinary air mail, please.
Anything of value in it?
A postal order for four hundred dollars.
In that case, you'd better have it registered.
Will I be informed when my friend gets the letter?
Yes, when your friend gets it, he'll sign a receipt, which will be sent to you by mail. Then you can be sure it's been received.