This is part two of what was mostly a cross-post of this Quora post.
The song is this one, and the lyrics go:
もしもこの世に汚れがなければ
姿を変えずに愛し合えたのに
どうして時は衆を分つの
ねえそばにいて今だけ
あなたがいるから私は強くなる
誓いの指輪きらきらきれいね
You will realize 小さな夢も
You are the one 心満たされる
夜のハイウエイバイクを飛ばして
はしゃいだ自由を持て余すくらい
この目で見て触れて分かる
確かなものがあったね
あの日の二人にすべて戻らせるなら
ひざまづく意志になるまでに祈るよ
We can still be free 百まで数えて
Never wanna stop 心解き放つ
あなたがいるから私は強くなる
誓いの指輪きらきらきれいね
You will realize 小さな夢も
You are the one いつか叶えられる
In transliteration:
Moshi mo kono yo ni kegare ga nakereba
Sugata wo kaezu ni aishiaeta noni
Doushite toki wa shū wo wakatsu no?
Nee, soba ni ite ima dake
Anata ga iru kara watashi wa tsuyoku naru
Chikai no yubiwa kirakira kirei ne
You will relize chiisa na yume mo
You are the one kokoro mitasareru
Yoru no haiuei baiku o tobashite
Hashaida jiyuu o moteamasu kurai
Kono me de mite furete wakaru
Tashika na mono ga atta ne
Ano hi no futari ni subete modoserunara
Hizamazuki ishi ni naru made inoru you
We can still be free hyaku made kazoete
Never wanna stop kokoro tokihanatsu
Anata ga iru kara watashi wa tsuyoku naru
Chikai no yubiwa kirakira kirei ne
You will realize chiisa na yume mo
You are the one itsuka kannaerareru
And this is the translation attempt I posted to lyricstranslate, with one or two edits:
Even if there were no impurity* in this world LT has "contamination"
So that [we] could've loved each other without having to change our looks…
Why does time separate [simple] people? "simple" was added here.
Hey, be by [my] side, at least now
Since you're there, I get stronger
The ring of [my] promise is sparkling, beautiful isn't it?
You will realize even [my] small dreams
You are the one, [my] heart is satisfied
On the highway at night riding a motorbike
Till [I] don't know what to do with the freedom of making merry
[I'll] see with these eyes and touch, and understand
That this has been real [lit. That there has been a real thing [between us]]
If it will let everything return to [how it was] in the days of us two,
[I] will pray till [I] want to fall on [my] knees
We can still be free, count till a hundred
Never wanna stop, I will set my heart loose
Since you're there, I get stronger
The ring of [my] promise is sparkling, beautiful isn't it?
You will realize even [my] small dreams
You are the one, [my] heart is satisfied
I also asked a question on Quora about this attempt.
The second question is a matter of singular and plural in the following two lines:
誓いの指輪きらきらきれいね
You will realize 小さな夢も
Japanese doesn’t mark number, so it could be “the ring of the promise”, “the rings of the promise”, “the ring of the promises”, “the rings of the promises”, and also “even the small dream” or “even the small dreams”. I don’t recall “no” marking material, so “the ring of vows” seems wrong. I was taking this to mean an engagement ring, so “the ring of the [=our] promise”, and then what small dream are we talking about? I’d go with plural, so “even the smallest dreams I have”. Is there any reason to do otherwise?