זה היה "יותר מדי טוב מכדי להיות אמיתי", חבל שלא חשדת מספיק
"You meet someone you think is a really Nice Guy/Girl, or perhaps you meet a favorite celebrity for the first time, thinking that they'll be just as warm-hearted and cool as they are on camera. However, something happens to show their true colors, revealing an immature brat, total Jerkass, or even outright villain."
"Congratulations. You've just met the Bitch in Sheep's Clothing — the polar opposite of a Jerk with a Heart of Gold."
"The Wounded Gazelle Gambit is a favorite tactic of this sort of antagonist, and if they are genuinely evil, expect them to be a Villain with Good Publicity."
"It's also worth mentioning that this trope isn't exclusive to female characters. The title is a play on "Wolf in Sheep's Clothing," and can apply to any gender. All it requires is a person appears to be nice, but is actually cruel and/or manipulative."
http://tvtropes.org/pmwiki/pmwiki.php/Main/BitchInSheepsClothing