JuniperBug
Rainbow Bird of Friendliness
I usually believe it's the responsibility of the manager to have that sort of conversation with an employee, especially if more than one of the team has raised the issue. As a former district manager with a retail chain, that unpleasant duty often fell on me.
If you do have a solid personal relationship with this person, though, it would certainly be kinder if it came from you.
If you decide to take this on, don't make a special event of it. Look for a moment of natural privacy rather than doing a "Can we talk privately for a minute?" That alone will ease some tension for her, though it might drive you a little crazy waiting for the right opportunity. Just remember this will be a bigger deal for her than for you.
Be brief, informative and empathetic. Open with something that makes your intentions clear, and from there, be gentle but matter-of-fact. Ease the feeling of judgment by giving her some excuses in advance. Prevent paranoia and extra humiliation by saying it's only you who has noticed it. Here's a script, just for example:
"Hey, I think it's important for you to know this. I've noticed a slight odor around you lately, since the weather got warmer. I know there could be a lot of different reasons for this, but I just thought I should tell you before someone else notices. I wouldn't want to see you be embarrassed. I don't want to embarrass you either, but I just thought if it were me, I'd want to be informed. Okay?"
When you're finished, smile understandingly (close-mouthed is best) and give her a chance to respond if she wants to. Be prepared to listen. Be prepared to give advice, but only if asked.
This part is only secondary. If you can allow her to walk away first when the exchange is over, that gives her a little power back. Don't wait so long for her to make a move that it gets awkward, but keep in mind that if you walk away from her, it will feel more like you just swooped in and dropped a bomb on her, leaving her helpless.
Good luck with whatever you decide to do.
Wow this is so informative and perfect. Are you planning on writing a book on social interaction anytime soon?
PS - I definitely CAN'T copy and paste that into a text, can I? Curse face to face interaction. -,- so awkward.