沉鱼落雁非倾国
[chén yú luò yàn fēi qīng guó]
Literally 'Even if fish dive and geese fall out of the sky (because they’re mesmerized by her beauty), she is not the one to topple nations.' The phrase is based on a traditional Chinese compliment for someone extremely beautiful but implies the person does not seek fame or grand attention through that beauty.