Fàngxia yuànhèn, cái néng huòdé nèixīn de píngjìng.
Only by letting go of resentment can you find inner peace.
Tips
usage
怨恨 is stronger than 怨 alone. 怨 is complaint or blame; 怨恨 adds hatred to the mix. The progression goes: 不满 (dissatisfied) → 怨 (resentful) → 怨恨 (bitter hatred).