You can request a read receipt for an individual email message,
letting you know for certain the email has been opened? Just follow these easy steps:
From the Inbox, create a new mail message
Click the View tab then Options… button on the toolbar (of
the Message window)
Under the Voting and Tracking options section, click the
checkbox for "Request a read receipt for this message"
Click "Close" to close out of the Message Options dialog
box
Send the message
The receipt will be delivered to your Inbox once the message
has been opened