分手的原因让我惊呆
[fēn shŏu de yuán yīn ràng wŏ jīng dāi]
This means the reason of breaking up made me flabbergasted. It is a statement expressing the user's shock at the real reason leading to separation from a significant other. The profile name might suggest the individual has undergone a tumultuous breakup and wants to reflect that surprising situation in their nickname.