《One's Again》的詞曲由日本歌手平井堅創作完成，其全部歌詞如下：
中文詞：
忘不了 那一場雨
淋濕了思念 淋濕了心情
不說 不再提起
心痛也隨雨滴遠去
忘了 那一場雨
把所有的故事都留在昨天
當我們還在一起
是因為愛還沒來及開始
還愛著 愛著你
像一個夢 想讓它成真
不愛了 不愛了 遠走高飛
你的世界不再有我 我也可以自由
愛你 一百天 一千天 一萬天
我的愛永遠不會改變
愛你 一百遍 一千遍 一萬遍
我還是一個人 一個人 一個人
英文詞：
I can't forget that rainy day
Moisture soaked my thoughts and my mood
Don't say, don't bring up again
Pain in the heart will drift away with the raindrops
Forget that rainy day
All the stories left behind in the past
When we were together
It was because love had not yet begun
I still love you, like a dream that wants to come true
If I don't love you anymore, if I fly away
Your world will no longer have me, and I can be free too
I love you for a hundred days, a thousand days, ten thousand days
My love will never change
I love you again and again and again
I am still alone, still alone, still alone.