To decide or come to a conclusion about something.
何かについて決心する、または結論に達する。 (nanika ni tsuite kesshin suru matawa ketsuron ni tassuru)
"After much deliberation, he finally made up his mind and chose the first option."
"よく考えた末、彼はついに決心して最初の選択肢を選んだ。" (yoku kangaeta sue kare wa tsuini kesshin shite saisho no sentakushi o eranda)
to verify that someone or something is doing well
to keep one's plans or intentions secret
to stay cheerful even when facing difficulties
to offer assistance or support
an outstanding work of art or achievement
to campaign for a political position