Is there anyway to tell if someone has read your message or not?

I have an IPhone 4S… Sometimes I get "read at 4:30" or something and sometimes it just says delivered…
Is there a difference? And can I make so I always know when someone reads it?

Then your desperate af

Those are delivery receipt, and you may have it on but maybe the person your sending it to doesn't. Or doesn't want that to be sent. So it only gives a notification that it was sent. I don't think there is a way to make sure you get those receipts because it depends on the recipients of that function. And yes there is a difference, read means they opened it. And delivered means that they got it but haven't opened it yet.

The receiver has an option to turn that off so no one knows when its read, its up to them.