南城以南思念不归北城以北深海未眠
[nán chéng yĭ nán sī niàn bù guī bĕi chéng yĭ bĕi shēn hăi wèi mián]
Translated literally: 'South of the southern city where yearning stays unresolved, and North of the northern city where the deep sea remains restless.' This reflects the complexity of emotion: there's unresolved longing somewhere ('the place for longing'), and elsewhere ('restless') represents an unrestful inner state, perhaps symbolized through the image of a sleepless deep-sea.