不哭不闹不炫耀不吵不笑不倔强
[bù kū bù nào bù xuàn yào bù chăo bù xiào bù jué qiáng]
This translates roughly to 'No crying, no quarrelling, no bragging, no fussing, no laughing, and no obstinacy,' emphasizing an image of complete emotional calm and stability. However, it could also mean that these traits are a mask hiding deep, internal emotions.