In just three lines, the speaker compares another person to Chinese characters. The comparison is a clever one. Chinese characters are famously numerous and complicated, and learning them takes patience and years of repetition. Yet the speaker says that no matter how many there are, not a single one is forgotten. The "you" of the poem is treated like that vast, intricate writing system: something complex, made of many parts, and fully memorized.
The feeling underneath is devotion. The speaker has taken in every detail of this person, every gesture and quality, the way a dedicated learner holds onto each symbol. Nothing about the person has faded or blurred. The tone is quiet and understated, with no big declarations, which makes the claim feel sincere rather than showy. The mood is tender, a little wistful, and perhaps slightly obsessive. The poem doesn't tell us whether the "you" is a lover or someone lost, so we're left with the simple, lasting impression of a memory that stays sharp.