Not who you're looking for? Others named Isabella Whitney: English poet
“Beware of fair and painted talk, Beware of flattering tongues: The Mermaids do pretend no good For all their pleasant songs. Some use the tears of crocodiles, Contrary to their heart: And if they cannot always weep, They wet their cheeks by art.”
Quotes via Wikiquote (CC BY-SA), each with its original source.