Verb ないではすまない (Verb nai dewa sumanai)
Explanation
'Cannot end without doing', 'must do'—an unavoidable moral or social necessity.
Formation
Verb-ない form + ではすまない
Detailed Explanation
The grammar Verb ないではすまない expresses that something must be done (often for moral, social, or personal reasons) and cannot be left undone. It implies an obligation or inevitability, akin to 'I can't get away without doing it.'
Examples
失敗をしたら、謝らないではすまない。
Shippai o shitara, ayamaranai de wa sumanai.
If you make a mistake, you have to apologize—there’s no way around it.
この問題は重大なので、報告しないではすまない。
Kono mondai wa jūdai na node, hōkoku shinai de wa sumanai.
This issue is so serious that I must report it.
この映画はとても感動的で、泣かないではすまない。
Kono eiga wa totemo kandōteki de, nakanai de wa sumanai.
This movie is so moving that you can’t help but cry.
子供が間違えたら、教えないではすまない。
Kodomo ga machigaetara, oshienai de wa sumanai.
If a child makes a mistake, you must correct them—there’s no avoiding it.
Grammar content sourced from hanabira.org.