Wikipedia
Yuan or Yuanfen (; Vietnamese: duyên phận), "fateful coincidence," is a concept in the Chinese folk religion describing good and bad chances and potential relationships. It can also be translated as "destiny, luck as conditioned by one's past," or "natural affinity among friends." It is comparable to the concept of karma in Buddhism, but yuanfen is interactive rather than individual.
The driving forces and causes behind yuánfèn are said to be actions done in previous incarnations. The proverb yǒu yuán wú fèn (有緣無份), "have fate without destiny," is sometimes used to describe couples who meet, but who do not stay together, for whatever reason.
Scholars K. S. Yang and D. Ho have analysed the psychological advantages of this belief: by assigning causality of negative events to yuanfen beyond personal control, people tend to maintain good relationships, avoid conflict, and promote social harmony; likewise, when positive events are seen as result of yuanfen, personal credit is not directly assigned, which reduces pride on one side of the relationship and envy and resentment on the other.