I was that manager that had to tell an employee they stink. The lady had a touch of ADD or something but she was the sweetest and hardest working employee I had.
I just had to break it down gently like “there are times when we meet that I notice an odor. Maybe you don’t notice it so I wanted to let you know because I don’t want you to be oblivious to the fact that others notice it as well and may just be uncomfortable telling you about it. I don’t want anyone, especially upper management, to have a reason to not want to work with you. You are such a critical part of the team with so much potential I don’t want there to be anything that holds you back from reaching that potential.”
Got to make it about them and you’re telling them for their benefit.