誓言总是美得让人心碎
[shì yán zŏng shì mĕi dé ràng rén xīn suì]
This means 'Vows are always beautiful enough to break one's heart.' It conveys a poetic yet melancholic idea that promises, especially those in love, are often so perfect and sincere they seem too good to be true, inevitably leading to heartbreak.