Both "ju" and "väl" are used to give an indication about the truthfulness of a statement, though they do so in slightly different ways. While "ju" marks a statement as being an obvious fact, "väl" is used when the speaker believes something to be true but isn't certain, inviting the addressee to respond affirmatively or negatively. It works similarly to French's "n'est-ce pas". Compare the following: Du skrev ju brevet! (You wrote the letter!) Du skrev väl brevet? (You wrote the letter, didn't you?) Some helpful links: -https://diskuterasvenska.wordpress.com/tag/skillnad-pa-ju-och-val/ -https://freddassfiblogg.wordpress.com/2016/06/14/orden-nog-val-och-ju/ -https://en.wiktionary.org/wiki/ju#Swedish -https://en.wiktionary.org/wiki/v%C3%A4l#Swedish Hope that helps. :)