Translation of: 美しいと思ってしまったのだ


I would like to ask about the interpretation of the sentence below:

> 美しいと思ってしまったのだ

If I were to interpret it literally, it would mean

> The thing of unintentionally thinking that it is beautiful

However, the translation given is

> Struck me as profoundly beautiful

I am finding it difficult to draw the link between the literal meaning and the
given meaning. Is my literal interpretation of the sentence wrong?




> 美しいと思って **しまったのだ** 。

I think the しまった here means "unintentionally", or "unexpectedly" with a nuance
"although you might not think that way in normal circumstance" (related: [Verb
in ている form ends with しまう](https://japanese.stackexchange.com/a/26023/9831)),
or maybe "wind up/end up" (related: [「しまう」 as an auxiliary
verb](https://japanese.stackexchange.com/a/21029/9831)).

As for the のだ, it could be used to add an emphasis, add an explanatory tone,
or to mean "Actually, ..." "Surprisingly..." etc., depending on the context.
These threads might be of help:

  * [What is the meaning of ～んです/～のだ/etc?](https://japanese.stackexchange.com/q/5398/9831)
  * [How is the "のです" working here?](https://japanese.stackexchange.com/q/3349/9831)




> 美しいと思って **しまったのだ** 。

I think the しまった here means "unintentionally", or "unexpectedly" with a nuance
"although you might not think that way in normal circumstance" (related: [Verb
in ている form ends with しまう](https://japanese.stackexchange.com/a/26023/9831)),
or maybe "wind up/end up" (related: [「しまう」 as an auxiliary
verb](https://japanese.stackexchange.com/a/21029/9831)).

As for the のだ, it could be used to add an emphasis, add an explanatory tone,
or to mean "Actually, ..." "Surprisingly..." etc., depending on the context.
These threads might be of help:

  * [What is the meaning of ～んです/～のだ/etc?](https://japanese.stackexchange.com/q/5398/9831)
  * [How is the "のです" working here?](https://japanese.stackexchange.com/q/3349/9831)

