Decision
Determination
noun, する verb
It's been decided and determined. The decision has been made.
けってい
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. Just be sure to take note of the shortened けつ in 決. It goes to けっ.
クママンまんがの、アニメ化が決定しました！
They’ve decided to turn the Kumaman manga into an anime!
これはさいしゅう決定になりますので、その後の変更はできませんが、よろしいでしょうか？
This will be your final decision and it can't be changed later. Is that okay?
君の妹の結婚式と俺の母さんの葬式、どちらに出席するかの決定は君に任せるよ。
I’ll leave the decision of whether we’re going to attend your little sister’s wedding or my mother’s funeral to you.