Tā juéde fǎnzhèng yīliǎobǎiliǎo, shénme dōu bùyòng dānxīn le.
He felt that once it was all over, there was nothing left to worry about.
Tips
usage
一了百了 can be used positively (solving the root issue resolves everything) or darkly (death as an escape from all troubles). Context determines the tone - be careful in emotionally sensitive situations.
