Mail Add Another TextBox to "Body"

Thank you for reading.
How can I add a 2nd textbox to my email body?
When I add two lines, I only get the second line in the email.
Thus:
MyMessage.From = New MailAddress(Sender, SenderDisplayName) MyMessage.Subject = Subject.Text MyMessage.Body = Body.Text
My Message.Body = msgURL.Text

... so, how can I add the second textbox to the body of the email?
Thanks in advance!