That is funny yet sickening to think of bad breath with a rancid odor coming from her box too.
Actually, if you are friends with this girl - here is what you do.
You can say something like
"Hey, can I ask you a question and you won't get mad?"
Hopefully answer is yes.
"If you heard something about a friend of yours that wasn't really a big deal but might hurt their feelings, would you tell them if you thought they should know?"
Hopefully answer is yes, or, if she is smart she will put 2 + 2 together and ask what is going on.
Then tell her something like " well, I heard somebody make the comment that your breath was kicking and I told them to chill that you probably were had just eaten some italian for or something spicey. Anyway, I'm not trying to offend you or be abrasive, just as my friend I wanted to tell you what I heard".
If she insists on knowing who, just make up a name or say that asshole bill or that asshole mike, I don't think you know him and I don't know his last name.
Seriously, if she's your friend, and hot too, you owe it not only to yourself but also to mankind, do us the favor bro, and give baby the hint to practice a little better oral hygiene.
Then, if you do hit it and her pussy does smell foul, it's up to you to educate her on the beauty and magic of deuce and cleanliness down there my friend.