So this means, there're only a few tags for this component?
The easiest way for me would be to show the content of the rent house and buy house form in the notification. But when I tested them I got as administrator anonymous e-mails. The username and the sender info is shown as anonymous too, so I'm guessing username isn't the same like the name you have entered in the form.
I would give my notifications a general text, that our customer has to go to the backend to read them. I only wish how to fix that I can see WHO was submitting a rent or buy request except of seeing "anonymous"