说不出的言不由衷猜不透的不明所以
[shuō bù chū de yán bù yóu zhōng cāi bù tòu de bù míng suŏ yĭ]
'Words from the heart but can't speak out' combined with 'unsolvable confusion', suggests complex sentiments. It represents those mixed and deep feelings hard to articulate; emotions felt strongly but inexplicable even to oneself, embodying emotional ambiguity and difficulty.