我非是美人却蛇蝎心肠
[wŏ fēi shì mĕi rén què shé xiē xīn cháng]
The literal meaning is 'Although I'm not pretty, I've got venom within.' It portrays someone believing she or he does not possess beauty or outward appeal, yet they might consider themselves somewhat vicious inside. The term could refer to a self-effacing way, sarcastic manner, or just express a personal opinion about their own inner feelings and exterior appearance.