Meaning:
“国泰民安” literally means “the country is peaceful and its people contented,” and “脸” means “face.” A short video recently went viral on Chinese social media capturing the wedding ceremony of a young couple in Shandong Province. Many who have viewed it praise the serene and peaceful temperament of the bride, who has the oval-shaped face typical of a Chinese woman, unlike that of the more Western-looking influencers with a tipped chin and high cheekbones. Chinese netizens started to call this kind of big round or oval face by this term, saying that this appearance of feminine beauty can bring good fortune.
Example:
A: 听说你们班转来一个新同学？
Tīngshuō nǐmen bān zhuǎnlái yīgè xīntóngxué？
Is it true that there is a new student in your class?
B: 是的，一个长着国泰民安脸的女生。
Shì de ，yīgè zhǎng zhe guótài mín’ān liǎn de nǚshēng。
Yes. She’s a girl with a peaceful (big oval) face.