情不知所起一往而深很不知所踪一笑而泯
[qíng bù zhī suŏ qĭ yī wăng ér shēn hĕn bù zhī suŏ zōng yī xiào ér mĭn]
A complex sentiment expressed poetically: Love started unexpectedly but became profound; at times, its origins cannot be traced but could vanish with a smile. It embodies the enigmatic nature of feelings, starting deeply without knowing where or how it begins and may even fade just as mysteriously.