let's get one thing straight

expression Let's clear up any possible confusion, misunderstanding, or uncertainty (about something); let me make this perfectly clear. Before we get into this debate, let's get one thing straight—we are to focus solely on the topic at hand, so no deviating into unrelated subjects. Let's get one thing straight: I am the boss, and you are the employee, which means that when I ask you to do one thing, you're expected to do it.