legal requirement that you give a reason why you terminated employment.
My attorney also advised me NEVER to give a reason and also never give letters of recommendation.
I was pretty straight forward when I terminated employees, my manager as with me and I generally had this script "person x I am terminating your employment effective immediately. The office manager will escort you to collect your personal items. Your final paycheck will be sent to you within 3 days" (if payday was outside the 3 day window), and that was it.
I would stand up and leave the room and the manager would escort the person to their items and out the door.
I had a few employees that would ask why they were being terminated and my response would be "I am not required to give a reason, your employment here has ended".