私はあなたを知らなくない →私はあなたを知らない 学校に本が無くなくて →学校に本が無くて both case, it is not necessary to add ない Double negative makes sentence positive. This sentence I understand what you say, but grammatically incorrect FYI だけど →だから

Thank you Ryoko. In a website that shows the inflections of the adjectives, there was a negative form of ない adjective. It was written as　 なくない. I thought this negation of a negative word might mean something like " it is not that something isn't" etc. Thus, I have tried to construct some exercise sentences. What I intended to say was a similar thing that you have already written. if there is something like なくない how can I use it?

ない itself is the negative form of ある. 本がある (There are books.) 本がない (There aren't books.) 知る、知っている(to know) 知らない(not know) I think your sentence is more complicated to translate into Japanese. Do you want to say like "It is not because of that I don't know you. However I need more time"? If so, I would translate: あなたのことを知らないからというわけではない。時間が必要なだけ。 If I understood wrong, please let me know.