彼は会社を辞めて留学する決心をした。
He made up his mind to quit his job and study abroad.
何度も考えたが、まだ決心がつかない。
I've thought it over many times, but I still can't make up my mind.
彼女は二度と嘘をつかないと決心した。
She resolved never to tell a lie again.
両親に反対されても、彼の決心は揺らがなかった。
Even when his parents objected, his resolve did not waver.