中々(なかなか)Very, Quite, Considerably

When used in affirmative sentences, なかなか and かなり both convey the nuance that something exceeds expectations, e.g. なかなか美味しい ('It's quite tasty.') or かなり美味しい (essentially the same meaning). The main difference is that なかなか is often used in negative expressions to suggest that something is not easily done, e.g. なかなかうまくいかない ('It just won't go well.'), while かなり is not used this way.

なかなか means 'quite' or 'fairly' when used with positive expressions, e.g. なかなか面白い映画だった ('It was quite an interesting movie.') In contrast, なかなか～ない expresses difficulty or delay, meaning 'not easily' or 'hardly', e.g. 仕事がなかなか終わらない ('The work just won't end.')

なかなか and あまり～ない both express degree, but in opposite directions. なかなか implies exceeding expectations, e.g. なかなか美味しい ('It's quite tasty.'). In contrast, あまり～ない suggests a lesser degree, or falling short of expectations, e.g. あまり美味しくない ('It's not very tasty.').

なかなか dan けっこう adalah kata keterangan (adverbia) yang dipakai untuk menunjukkan seberapa tinggi tingkat atau kadar sesuatu. Dalam kalimat positif, keduanya bisa berarti 'cukup' atau 'lumayan'. Perbedaannya, なかなか sering dipakai dalam kalimat negatif untuk mengekspresikan kesulitan dalam melakukan sesuatu. Sementara itu, けっこう bisa berdiri sendiri (terutama dalam bentuk けっこうです) untuk dengan sopan menolak sesuatu, mirip dengan mengatakan 'saya sudah cukup' atau 'tidak usah, terima kasih'.

Both express degree, but with different implications. なかなか implies something is quite or unexpectedly good, e.g. なかなかいい店だね ('This place is surprisingly good.') あまり highlights an excessive degree that leads to an unintended or negative result, e.g. 緊張のあまり声が震えた ('I was so nervous my voice shook.')

Both emphasize degree, but differ in nuance. なかなか suggests something is quite or surprisingly so, often with a positive tone, e.g. なかなか面白い映画だった ('It was quite an interesting movie.') あまりに means 'too much' or 'excessively', and is often negative in tone, e.g. あまりに寒くて出かけられなかった ('It was too cold to go out.')

Though both contain なか, their meanings are different. なかなか is often used in negatives to express difficulty, like 'not easily' (なかなかできません), or in positives to mean 'quite' (なかなかいい). In contrast, のなかで means 'among' and is used when referring to one or more members of a group. For example, 果物の中でりんごが一番好き means 'Among fruits, I like apples the best.'.