What Is The Difference Between 「好きじゃないです」and 「好きではないんです」?


I understand that they both mean I do not like, but I'm not sure what exactly
「好きではない」means. Moreover, does the particle 'では'make a difference, or could you
have just used 'は'?




You seem to be asking two questions in one here, about the difference between
では and じゃ and also about what the presence or absence of ん means.

Number 1, じゃ is a contraction of では, like how 'can't' is a contraction of
'cannot' in English. では can be formal, or it can also imply greater emphasis.

Number 2, ん is a contraction of の in the のだ・のです structure. 好きじゃないです (and
好きではないです) is a plain statement. 'I don't like it.' With ん, there's a bit of an
explanatory nuance. Note that, directly following a noun or na-adjective,
のだ・のです takes the form ～なのだ・なのです, or ～なんだ・なんです contracted. This form cannot
directly follow a noun or i-adjective; 「好きではないなんだ」 is ungrammatical.

「今度、寿司を食べに行きませんか？」 'Will you go out for sushi some time?'

「遠慮しときます。魚は好きじゃないんです。」 'I'll pass. I don't like fish.'

As you can see, 好きじゃないんです explains why the person is turning down the
invitation.

