「<span class='vocab-popout' data-vocab-id='966'>警察（けいさつ）</span>はすべての悪者（わるもの）に必（かなら）ず罰（ばち）を与（あた）え<strong>ずにはおかない</strong>。」

小説（しょうせつ）、勇者（ゆうしゃ）：「<span class='vocab-popout' data-vocab-id='185'>どんな</span>手段（しゅだん）を用（もち）いても、かならず魔王（まおう）を倒（たお）さ<strong>ずにはおかない</strong>。」

「<span class='vocab-popout' data-vocab-id='849'>私（わたし）</span>はきっと<span class='vocab-popout' data-vocab-id='564'>彼（かれ）</span>に<span class='vocab-popout' data-vocab-id='429'>同（おな）じ</span><span class='vocab-popout' data-vocab-id='598'>手（て）</span>で仕返（しかえ）しをし<strong>ないではおかない</strong>。」

小説（しょうせつ）：「探偵（たんてい）は『<span class='gp-popout vocab-popout' data-gp-id='30' data-vocab-id='91'>この</span>残虐（ざんぎゃく）行為（こうい）の責任者（せきにんしゃ）を訴追（そつい）せ<strong>ずにはおかない</strong>』と意（い）を決（けっ）<span class='vocab-popout' data-vocab-id='138'>する</span>。」

「<span class='vocab-popout' data-vocab-id='564'>彼（かれ）</span>はまた<span class='vocab-popout' data-vocab-id='849'>私（わたし）</span>との<span class='vocab-popout' data-vocab-id='866'>約束（やくそく）</span>をすっぽかした。絶対（ぜったい）に<span class='vocab-popout' data-vocab-id='564'>彼（かれ）</span>に『<span class='vocab-popout' data-vocab-id='575'>ごめんなさい</span>』と言（い）わせ<strong>ずにはおかない</strong>。」

<div class='writeup-body'><span class='gp-popout' data-gp-id='945'>ずにはおかない</span> is a combination of the <span class='info-highlight' data-term='文語助動詞・ぶんごじょどうし'>classical auxiliary verb</span> ず, the <span class='info-highlight' data-term='格助詞・かくじょし'>case-marking particle</span> に, the <span class='info-highlight' data-term='副助詞・ふくじょし'>adverbial particle</span> は, and the standard negated form of the う-Verb 措（お）く, 措（お）かない, ‘to set aside’, or ‘to leave as is’. It is interpreted as ‘(A) will definitely happen’, or ‘I will not fail to (A)’.<br>
This is a formal expression that literally means ‘I cannot leave it as it is with (A) undone’, and therefore indicates strong will to complete the action that is reflected in the standard translations.<br>
As this structure begins with ず, it will only be used with verbs.<ul class='writeup-examples--holder'>
 <li class='writeup-example'>
<div class='writeup-example--japanese'>
あんなひどいことをした人（ひと）だから、警察（けいさつ）も捕（つか）まえ<span class='gp-popout' data-gp-id='945'>ずにはおかない</span>だろう。</div><div class='writeup-example--english'>
I am sure the police will not fail to arrest that person, since they did something so horrible.</div></li><li class='writeup-example'><div class='writeup-example--japanese'>


メディアにも取（とり）り上（あ）げられたから、警察（けいさつ）も調査（ちょうさ）をせ<span class='gp-popout' data-gp-id='945'>ずにはおかない</span>。</div><div class='writeup-example--english'>
Since it was covered by the media, the police will certainly investigate.</div></li></ul>
Alternatively, ないでは may replace ず. This will be seen as ないではおかない. However, the meaning will not change at all.<ul class='writeup-examples--holder'>
 <li class='writeup-example'>
<div class='writeup-example--japanese'>
こんなことをされたのだから、お客（きゃく）さんも訴（うった）え<span class='gp-popout' data-gp-id='945'>ないではおかない</span>だろう。</div><div class='writeup-example--english'>
Since they did such a thing to the customers, they would certainly sue them.</div></li><li class='writeup-example'><div class='writeup-example--japanese'>


この犬（いぬ）は30キロになるから、躾（しつけ）に力（ちから）を入（い）れ<span class='gp-popout' data-gp-id='945'>ないではおかない</span>。</div><div class='writeup-example--english'>
Since this dog will become 30kg, I will not fail to train him.</div></li></ul>


<div class='writeup-caution'><div class='caution-header'>Caution</div>Due to this grammar expression showing strong will to not give up until (A) is done, it will often be used with causative verbs in (A). This indicates that the speaker is determined not to quit until they can make another person do something.<ul class='writeup-examples--holder'>
 <li class='writeup-example'>
<div class='writeup-example--japanese'>
あの人（ひと）のスピーチは聞（き）く人（ひと）を感動（かんどう）させ<span class='gp-popout' data-gp-id='945'>ずにはおかない</span>。</div><div class='writeup-example--english'>
That person’s speech will not fail to move the audience.</div></li></ul></div></div>

Grammar Info

ずには措(お)かない

will definitely, will certainly, bound to, not fail to