Note: 1. The stress on this sentence is on "not." In other words, he's saying that there is no way he wouldn't notice how she was feeling.
2. This is a more literally correct translation of this line. The emotion/tone/connotations of the original Japanese lyrics are probably better understood by translating it as "How could I ever forget you?" (As in "it would be impossible for me to forget.")
3. Inaba-san doesn't actually use the word "you," but from the context it’s clear that he is either referring to the person that's "the one" or referring to the fact that she is "the one."

O N E

Shizuka sugiru yoru da, mimi ga uzuku hodo
Boku mo kimi mo dare mo, nemutte nanka inai no ni

Kotoba ga mada taisetsu na koto
Tsutaerareru nara mata nandemo ii kara
Koe wo kikasete yo

Wakatteru-tte, mou ikitain darou
Kizukanai wake nai darou, you're the only one
Donna koto demo muda niwa naranai
Bokura wa nanika wo akirameru wake ja nai

Yoake no shunkan wa itsudatte taikutsu datta keredo
Itsumo to chigau taiyo ga, heya no katasumi terashita

Yume ga aru nara oikakereba ii
Maru de gypsy mitai ni jiyuu ni samayoi nagara, bokura deattan dakara...

Mata aimashou, itsuka, dokoka de
Wasureru wake nai darou, you're the only one
Door wo akereba michi wa nemutte
Fumidasareru ippo wo machikogarete iru

Yukai na toki dake omoi dashite
Namida ni oboreru tamaniwa sore mo ii
Tomoni sugoshita hibi wa bokura wo tsuyoku shite kureru yo
Kono mune wo harou~
Zettai aimashou, itsuka, dokoka de
Wasureru wake nai darou~! Baby, you're the only one...
Hi ga mata nobotte yuku...

The night is far too silent that it makes my ears throb in pain
Even though neither you nor I nor anyone else is asleep

If words still have the ability to convey what's important
Then I don't care what it's about, let my hear your voice again

I know, you want to leave already, right?
How could I not notice? (1) You're the only one
Whatever it is, it won't be in vain
Because it's not like we've given up on something

The break of dawn was always such a boring moment
But a different sun then usual shines through to the corner of the room

If you have a dream, go ahead and pursue it
Because it was while wandering freely like gypsies
That we found each other

Let's meet again, someday someplace
There's no way I'd ever forget you (2) (3) You're the only one
When you open the door, the road is asleep
Tired of waiting for you to take your first step forward


Remembering only the happiest times you drown in your tears
There's nothing wrong with that from time to time
The days we spent together will make us stronger
So let's hold our heads high
Let's meet again no matter what, someday someplace
There's no way I'd ever forget you (2) (3) Baby, you're the only one
The sun is rising again

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