How can I make sure my files have been sent to another user?

<p>I received emails saying my files had been uploaded to another user. But when I look in my own Dropbox account, I don't see the files. It worries me that they may not have been accepted by the other user in time. I would like to see the file and/or the status of it in my Dropbox to indicate it's been received, but there's nothing there. How can I be sure these items were received and viewed by the person who requested them?</p>