"A csokoládé édes és finom, de nem kérek."

Translation: The chocolate is sweet and tasty, but I do not want any.

[AlsEenPoffertje]

Would it be correct to use "kérem" instead of "kérek"?

[jsiehler]

I think that would actually match "I do not want it" better than kérek does. I would say the sentence with kérek probably better translates as "...but I don't want any." (Better let a native speaker weigh in to be certain, though.)

[vvsey]

You are absolutely correct.

With the "kérek" version, you could also add "belőle" - from it. "Nem kérek belőle."