亡心忘你疯人封心
[wáng xīn wàng nĭ fēng rén fēng xīn]
The term conveys a person who might feel so deeply heartbroken and lost after some betrayal, to an extent where they choose to 'close their heart,' meaning no longer wanting to feel or express emotion because of past pains, indicating a strong sense of self-protection against future suffering.