忘需无心才可亡
[wàng xū wú xīn cái kĕ wáng]
'To forget, only heartlessness can lead to oblivion,' emphasizes the theme of needing complete emotional detachment to genuinely achieve forgetting or erasure of memories and feelings. It speaks of the difficulty and maybe even cruelty involved in wiping out intense emotions which can imply that only someone without conscience (or empathy) could accomplish such a feat of letting go fully and finally.