How to tell someone has read your text, even if they have it set where you can?

I have an iPhone so I use I message all of the time. My friend showed me how to make it so that someone can't tell that I've read their text. Us there a way to tell if the person I'm texting has the same thing? I know that kind of goes against the whole point, but I sent an important message to a friend and I need to know if she got it or not. Is there some type of loophole?

Of course not, if they turn it off then you won't know.