the average de-conditioned person would prefer not to exercise at all which is why they carry those adjectives. They are also usually intimidated by the standard recommendations of 150 minutes of exercise per week which sounds like a lot when you not doing anything at all.
I find that encouraging people to start with small steps can get a foot in the door. A message like ‘The journey of 1000 miles starts with a single step’ tends to be reassuring. It may also be a of importance to allied health professional to know that they are not throwing their patients into the arms of a ‘no pain, no gain’ type of trainer. Since you are NASM certified, you could also explain the OPT model.