哥一笑倾你孤身姐一笑倾城倾国
[gē yī xiào qīng nĭ gū shēn jiĕ yī xiào qīng chéng qīng guó]
This implies brothers' charming smile wins over loneliness, while sisters have such beautiful grins that could captivate whole city. It originates from classic praises towards exceptionally attractive men or women and reflects admiration.