孟婆汤里品出了思恋奈何桥里走出了想念
[mèng pó tāng lĭ pĭn chū le sī liàn nài hé qiáo lĭ zŏu chū le xiăng niàn]
This refers to the belief in Chinese culture that drinking Mengpo soup at the River of Reincarnation helps one forget all memories from previous lives. Here it metaphorically describes a feeling of yearning and nostalgia persisting even after supposedly letting everything go or forgetting past life experiences.