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. 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.

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. 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.