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to be disappointed; to be dejected; to be downhearted; to be discouraged; to be disheartened; to lose heart; to feel let down
to feel exhausted; to feel drained
結果を聞いてがっかりしました。
I was disappointed hearing results.
がっかりさせてごめんなさいね。
Sorry for disappointing you.
試験に落ちてがっかりしたよ。
I failed the exam and was down.