How do you translate not really in Japanese?

Answer 1

In general, 別に～ない (betsu ni - nai) means "not particularly x" which is roughly the same as saying "not really x" in English. An example of this would be 別に何でもない (betsu ni nandemo nai), "not particularly anything". There is also the case of simply 別に (betsu ni) as a response, which has due to colloquialisms in the language come to mean "not particularly" and can therefore be used in response to mean "not really". For example, you are talking to a classmate and are asked the question: 電気工学の授業は難しい？ (denki kougaku no jugyou ha muzukashii; is your electrical engineering class hard?). You could respond with, いいえ、別に (iie, betsu ni; no, not really).