en_tn/pro/18/02.md

A fool finds no pleasure in understanding, but only

"A fool does not care about understanding, but only about" This means the fool considers "understanding" the opposite of pleasure. Alternate translation: "A fool detests understanding and only finds pleasure in" (See: rc://en/ta/man/translate/figs-litotes)

but only in revealing what is in his own heart

This means that the fool only finds pleasure in telling other people what he feels and desires in his heart. Alternate translation: "but only in telling others what is in his own heart" (See: rc://en/ta/man/translate/figs-explicit)

what is in his own heart

The contents of a person's heart refers to the person's thoughts and feelings. Alternate translation: "what he thinks" (See: rc://en/ta/man/translate/figs-metonymy)