How do I tell my nanny she has body odour????

Hi everyone,

So my nanny has terrible body odour and it's so bad that when she has been attending to the babies the smell ends up on them. When you walk into the house you can literally smell it in the whole house. it was so embarrassing when I had friends over this weekend as I walked in with them and had no time to rectify it before they arrived.

She's been with us for three months now and one of the first things i had in the list of to dos that i wrote for her was to make sure everyday that she has bathed, and applied roll-on/deodorant before starting work. I sat down with her and was read it out to her and explained the importance of it esp because she is dealing with kids. I sat down with her about it again last week and said to her that now that we are all supposed to to stay fresh throughout the day, moreso now that it's hot. even if it means freshening up through the day. she changed for two day and now its the same thing again. she is very passive aggressive and having told her three times already I'm not sure how else to say it in a nanny that won't be offensive. since she has been here we also suddenly have cockroach issue and that to me is an cleanliness issue. I'm realising that she is quite them messy person as her room is always in a mess, she can't do simple things like brush my daughters hair after a bath, or wipe her mouth clean after a meal. She is very offish when asked to do anything most of the time. takes shortcuts....so stressful considering the point was to have help but i spend more time asking her to redo things or take care of herself. My kids have adjusted to her and she is god with them generally. Ironically whenever when it's her day off, she is sparkling clean, looks fresh and has no odour so im not sure if she it's an issue of having a bad attitude towards her work maybe?. I have also to given her toiletries in the hope it'd help, but no luck. Any one had this happen before? how did you deal with it?