en_tn/pro/28/13.md

hides his sins

"covers his sins." This is the opposite of confessing and forsaking sins, and is spoken of as covering sins rather than bringing them into the open (See: rc://en/ta/man/translate/figs-metaphor)

will not prosper

"will not succeed" or "will not advance"

the one who confesses them and forsakes them will be shown mercy

This can be stated in active form. AT: "God will show mercy to the one who confesses and forsakes them" (See: rc://en/ta/man/translate/figs-activepassive)