こそ
For sure, For certain, Even more so, Underlined or bolded text
Structure
Explanation
こそ is a special adverbial particle in Japanese that typically takes the place of the particles を or が. Its function is to emphasize that the preceding noun or noun phrase is the most crucial piece of information within the sentence. In English, this effect is often conveyed through vocal stress on a word, or by using italics or bold lettering for written emphasis. If we were to draw a direct parallel, phrases such as 'it is specifically (A)' or '(A) is the very one' capture the nuance of こそ very well.
こそ can be attached directly to any noun that would normally be followed by を or が, whenever that specific noun needs to be highlighted for contrast or importance.
- これこそ私が欲しかったものです！やっと見つけました。This is the very thing I've been wanting! I finally found it.
- 今年こそ試験に合格するぞ！This year for sure, I'm going to pass the exam!
Caution
The reason こそ can take the place of が, but not は, is related to their core functions. が is used to identify new or specific information, while は is used to set a general topic for discussion. Since their roles are essentially opposites, こそ's job of emphasizing aligns with が. To make it simpler, you can think of the three particles in terms of their highlighting strength:
は- Introduces a topic, with light emphasis.
が- Points out specific information, with moderate emphasis.
こそ- Pinpoints specific information, with intense emphasis.
Fun Fact
A common use of こそ is following a name or pronoun when responding to someone's gratitude or apology. It is a way of turning the sentiment back to the other person, implying that you are the one who should be expressing it.
- いいえ、こちらこそ気をつけなくてすみません。Not at all, I'm the one who should apologize for not being careful.
Examples
彼こそその仕事に相応しい。
He is the one who is suitable for that job.
来年こそ試験に合格するぞ！
I will pass the exam next year!
先生が「努力こそ大切だ」と教えてくれた。
My teacher taught me that 'effort is what is important'.
ピンチの時こその実力じゃないか。
Without a doubt, this is when true ability is shown, isn't it?
みんなが諦めた時こそ、チャンスなんだ！
That moment when everyone else gives up is my chance!
それでこそ、わが弟子だ。
That's exactly why you're my apprentice.
それこそが、私達が解決すべき本当の問題です。
I believe that, indeed, is the real problem that we should solve.
今日の試合こそ勝ちたい。
I really want to win today's match.
こちらこそどうぞよろしくお願いします。
It is I who should be saying: it's a pleasure to be working with you.
ごめんなさい、私こそもっと早く連絡すべきでした。
I'm sorry! It was (for sure) me who should have contacted you earlier.
忙しい時こそ、少し休むべきだよ。
Busy times in particular are when you should take a little break.
家族を幸せにできれば、それこそが私の願いです。
If I am able to make my family happy, that (for sure) is my greatest wish.