Q: The last line in TFiOS is important, but what if it does not translate properly into another language? Is that whole idea of marriage going to be lost?
Yes. This is inevitable in translation. (Many other lines that are a big deal in English may also get lost in translation.)
But here’s what is often overlooked: Just as there are inevitably losses in the translation process, there are also opportunities. There are ways in which a translation can become richer than the original text.
This is an extension of books belonging to their readers and novels being inherently collaborative. We think, “Well, the author’s original text is the ideal text,” but A. there is no actual “original text” because the entire process of creating the novel is collaborative, and B. it is perfectly possible for a translator to improve an author’s text—at least in places—by working thoughtfully with a different set of linguistic tools.