口が裂けても くちがさけても (I) won't (say) anything no matter what (expression is followed by negative verb relating to say, answer, etc.) to not (tell) even under any threat exp Advanced ➥
口が裂けても言えない くちがさけてもいえない (I) won't say anything no matter what; to be unwilling to tell even under threat exp adj-i Advanced ➥