青楼满座谁懂人心寂寞
[qīng lóu măn zuò shéi dŏng rén xīn jì mò]
'Full House in the Brothel, Who Understands the Loneliness of One's Heart' refers to an ancient brothel (qīnglóu) often used poetically in literature, juxtaposing external busyness and internal loneliness. It highlights the emotional solitude that one might feel despite physical company or surroundings.