Negative adjective grammar

Question

I wonder what is the difference between these two patterns when using negative adjectives:

これは面白いマンガじゃありません。
これは面白くないマンガです。

Answer 1

Japanese

今回の場合の1つ目の例である

面白い漫画じゃありません

の意味は、「面白い」と言う修飾子を「じゃありません」と言う単語によってその言葉の意味を打ち消しています。

対して、2つ目の例である

面白くない漫画

と言うのは、打ち消しなどを使わず「面白くない」と言う単語を最初から使うことで、

「よりそれを直球に、わかりやすく」伝えています。

そして本題の2つの違いですが、こちらは前述したような単語の違いはあるものの、伝わる意味は殆ど同じです。　ただ、どちらかというと「面白くない漫画」のほうが「面白い漫画じゃない」よりも聞いたときにネガティブな印象を捉えます

English

The first example in this case,

面白い漫画じゃありません

means the use of negation cancels out the word "面白い".

And in the second example in this case,

面白くない漫画

means by using the word "面白くない" from the beginning, instead of using strikethroughs, etc., it conveys the message "more directly and plainly.

By using the word "面白くない" from the beginning without using strike-throughs, etc., it conveys the message "more directly and clearly.

The difference between the two is that the meaning conveyed is almost the same, despite the aforementioned differences in vocabulary.

And now to the main issue of the difference between the two. Although there are some differences in vocabulary as mentioned above, the meaning conveyed here is almost the same.　However, if anything, "面白くない漫画" captures a more negative impression when heard than "面白い漫画じゃない”.

If I said not fluent English please tell me

Answer 2

I guess, it's the same difference as the difference between "This isn't an interesting manga" and "This is uninteresting manga". Or to put it differently - the difference is the scope of negation - does it negate entire sentence (first one) or adjective only (second one).

I don't know which one is more common/natural-sounding.

Update: answer by @Qwj_38 seems to suggest that これは面白くないマンガです。 conveys stronger emotions. I guess, once again, the same as English. And at the same time it's more natural