he's the one

他是其中一个，或者他是一个。
都可以用啊。ONE可指代前面讲过的人或者相应的事物啊

没有语境不适合翻译。
先把He's the one简单地理解成“你要找的人就是他”，或者简单点说“就是他”。

比如警察在寻找逃犯，现在有人帮助指点坏人是哪一个时说声“he's the one".

某个女士不知道该爱谁，突然出现了一位你觉得不错的适合她的男的，你可以说”he's the one“。

当然我们也可以很自信对某位异性说“I am the one(for you)!" ：）

最后来欣赏一首你可能熟悉的歌的歌词：
You are the candle, love's the flame
A fire that burns through wind and rain
Shine your light on this heart of mine
Till the end of time
You came to me like the dawn through the night
Just shinin' like the sun
Out of my dreams and into my life
You are the one, you are the one
CHORUS:
Said I loved you but I lied
'Cause this is more than love I feel inside
Said I loved you but I was wrong
'Cause love could never ever feel so strong
Said I loved you but I lied
With all my soul I've tried in vain
How can mere words my heart explain
This taste of heaven s