I manage a team and earlier this year had to tell someone that she smelled. It was the worse thing I've ever had to do as a manager.
The back story was that she'd worked in the team for about 2 years and pretty much always smelled. I wasn't her manager initially but the one at the time didn't want to upset her.
She smelled so bad (sweat), from when she came in in the morning. You knew if she'd been in a room as it would smell for ages afterwards.
When I became manager I didn't initially tackle it either for fear of upsetting her but eventually I realised it wasn't fair to my team (and a sign of me being a poor leader) if I didn't handle difficult situations. People would very regularly come to me complaining about how bad she smelled.
I took her into my office when everyone else was leaving (so not near by) and said I knew this would be an uncomfortable conversation but that she had a body odour.
She was so shocked and upset. I initially was mortified but I actually found once I'd started the conversation it got easier.
She said she bathed twice a day and wore fresh clothes everyday (we wear a uniform so get changed into clean uniform provided for us when we get to work).
I asked if she was ok and needed any support, she said no.
Later that night she emailed me and said she was really surprised and upset about the conversation, that no one had ever told her that before. She finished the email by saying she would like me to give her an update in 2 weeks time about whether it was better.
From the next shift she no longer smelled, and that was a few months ago. When I spoke to her at the 2 week mark she said she had done absolutely nothing different. She clearly had as she no longer smells.
I still cringe thinking how embarrassing the whole situation was, I am pretty sure she hates me now...