無駄ではなかった

was not in vain

→ 無駄だ
phrase Rare #32,504
was not in vain Used to say that someone's effort, sacrifice, experience, or action was worthwhile and produced a meaningful result. The present form 無駄ではない means “is not in vain.”
JA: 彼女の努力は無駄ではなかった。
EN: Her efforts were not in vain.

私の忠告彼女には無駄ではなかった

My advice was not wasted on her.

彼はアメリカへ行った無駄ではなかった

His trip to America was not in vain.

彼の死は無駄ではなかった

His death was not in vain.

彼らの努力は無駄ではなかった

Their efforts were not in vain.