So it's just the your plural as well rather than jouw being the your singular?
And this is when I wish the word "y'all's" wasn't considered "bad English"... ;-)
It's good in the southern US. In Canada at least a "your plural" might be clarified with something like "I have your guys' books." although maybe not that proper. I would say most English speakers don't really think of your as having a plural.
In the tips + notes, it says there is no way to say "This is yours [plural]," stand-alone with no noun following it. Is the only way to say this then „Dit is van jullie.“?
Yes, jullie doesn't have a standalone variant. This is an exception rather than the rule, however:
Dit is het mijne / onze / jouwe / uwe / zijne / hare / hunne.
A lot of these are rather rare in daily speech, though.
Following the same pattern would be something like jullieë, I guess, but I've never heard that in my life. It's definitely not part of standard Dutch. Maybe one day it'll catch on, though. ;-)
Where is the difference between hun and jullie ? Could i replace jullie with hun in this sentence?
Hun boeken would mean their books. Jullie boeken means your books (plural). So no, you can't.
So 'jullie' is you and yours? Also being singular and plural depending upon context?
No, „jullie“ is only plural "you" or plural "yours." In the Tips and notes section for the Possessives skill, it gives this example: „Ik geef jullie jullie boeken.“ which translates to "I give you (plural) your (plural) books." However, to avoid saying „jullie“ twice back-to-back, the second one [the possessive adjective] becomes „je“: „Ik geef jullie je boeken.“ Hope this helps
If we do the reverse then the english "your" can be translated to both plural "jullie" and singular "jouw". Right?