Sending a private message (which goes through our doodlekisses email inbox) is best. But another way you could do it is to choose in your settings to moderate the comments on your page, so you get to read the comment before approving it before it is posted publicly for others to see. So if a comment contains private info, you can keep it private and not allow others to see it. However, you can only control these settings for comments made on your page, not for comments you make on other people's pages (they control their own settings).