はしない・
A flat "certainly won't". は between a verb stem and しない denies that the thing will happen at all. In casual speech the は turns into や: 忘れやしない.
Don't worry. I won't make you carry the blame alone.
I would never believe such a baseless rumor.
How to form it
Verb ます-stem + はしない／やしない
行きます → 行きはしない, 行きやしない. Polite はしません, past はしなかった. A する-verb usually puts は after its noun: 後悔はしない.
- Often answers
- What someone expects, fears or claims: "you'll give up", "he's forgotten".
- はしない
- Firm and deliberate: a vow, a refusal, a calm "that won't happen". Fine in writing too.
- やしない
- Casual speech: usually rough, impatient or breezily reassuring, and often a little old-fashioned. Also how people grumble about what someone never does.
In use
You're going to give up halfway again, aren't you?
I will not give up. This time I'll see it through.
He forgot his promise, you say? He'd never forget.
Nobody is going to come on a rainy day like this.
Rumor had it that he had fled, but he never left the town.
聞きゃしない, 知りゃしない
Said fast, やしない runs into the stem: 聞きやしない becomes 聞きゃしない. A short ば-form looks the same (やりゃできる is やればできる), but straight before しない it is やしない: やりゃしない, "won't do it".
However many times I say it, my kid just won't listen.
Nobody has any idea what he really thinks.
泣きはしなかったが: not …, but
Before が or けれど, はしない is often milder: "didn't go so far as to …, but".
She didn't actually cry, but her voice was shaking.
はしない or もしない?
He doesn't even apologize.
も is "even": it is the least he could do, and he doesn't. You blame him.
He will not apologize.
は is the flat no: it isn't going to happen.
Close neighbours
Its other shape, もしないで, is "without even …ing".
He complains without even looking at the documents.
っこないN3
Also casual, also on the ます-stem, but about what can't be done or won't work out.
There's no way I can do a problem like that.
The same flat denial for an adjective or a noun.
It's all right. This injection doesn't hurt a bit.
Check yourself
1Which one is right?
何が
Choose an answer to see why.
2What does this mean?
誰にも
Choose an answer to see why.
More sentences
Going without food for a day won't kill you.
You think money will move him? He'd never budge on terms like those.
Him, betray his friends? He'd never do a thing like that.
Some say the deadline should be extended, but we will not change our policy.
He apologized, you say? He never did, right to the end.