This is the 435th most frequent Japanese word.
決め
"決め" (kime) means "decision" or "determination."
In this sentence, '決めました' is used to express making a decision about watching a movie.
今日は映画を見ることに決めました。
I decided to watch a movie today.
Here, '決めた' indicates determining or finalizing the victory in the match.
彼は試合の最後で勝利を決めた。
He decided the victory at the end of the match.
In this case, '決める' refers to the process of making a significant life decision regarding one's career path.