This is the 1989th most frequent Chinese word.
確定
"確定" means "to confirm" or "to determine."
Here, '確定' is used as a verb meaning 'to confirm' or 'to ensure'.
我已確定參加明天的會議。
I have confirmed my participation in tomorrow's meeting.
In this sentence, '確定' acts as a verb meaning 'to be sure' or 'to affirm'.
確定是他完成了這項工作。
It is confirmed that he completed the task.
Here, '確定' implies a form of inquiry or analysis to establish something concretely.