Nein, Deutsch ist nicht schwer. Kein is used when a noun is negated. In other cases we use nein.
@SunilGerman14 күн бұрын
If we analyse the sentence further, it should be like: Ist Deutsch schwer? So here for negating schwer we use nicht schwer because schwer is an adjective, not noun. The main point behind nein in the beginning of the sentence is that it negates the effect of the whole sentence.