Emails with privileged content / google ?

I use the plugin to email wholesale clients for my products. I would like to include pricing information but would not wish that information to become public or be indexed by google.

I’ve seen the past that the emails do have a URL associated with them, does anyone have any insights into a foolproof process of keeping those URL;s / the content of the emails out of google indexes etc and thus the content of the emails reasonably private ?