"Já ji nepotřebuji."

Translation: I do not need her.

[steampunkgiraffe]

what is the difference between potřebuju and potřebuji?

[JanLyko]

"Potřebuju" is colloquial/informal.

[andrew_lim]

"I do not need it" is wrong. Is this because for an inanimate object, you would use "to" instead of "ji"?

[kacenka9]

No, it was wrong because it was missing. If we talked about a pencil, in Czech it would be JI but translated to English we get IT.

Edited

[queentoricorn]

I think it is not about animate/inanimate object, "ji" simply suggest that it will be feminine noun, and it doesn't matter if it is animate or not (you only distinguish that with masculine nouns), so you would say "Já ji nepotřebuju." when talking about both about a girl (dívka) and a pencil (tužka). You would use "Já to nepotřebuju." (I don't need it.") when talking about neuter nouns.

[ZenaSarky]

Why is nepotrebuju wrong in this instance? I don't think we can tell whether it is a formal or informal context

[BoneheadBass]

It isn't. "Já ji nepotřebuju" is accepted in the reverse (EN-to-CZ) exercise.