Only moderators can view deleted comments. I am fairly certain there is no way to know for sure that there are deleted comments on a post, other than of course remembering that one was there and seeing that it's not anymore.

The idea of notifying commenters of comment deletion [has been discussed on MSE](http://meta.stackexchange.com/q/105338/295684). It's unlikely to be implemented for two reasons:

1. Comments are never supposed to be permanent. If there's anything critical in them, that information should be used to compose or improve a post.
2. Some users have posted *a lot* of comments that eventually became obsolete. Poking such users every time a comment of theirs disappears would generate quite a bit of noise in their inboxes.

If you do something *really, horribly bad* in a comment, it's possible that a moderator will message you privately or poke you in chat. But one of your comments being deleted doesn't usually mean you did anything wrong; they're just being cleaned up.