expression
no matter what; wouldn't say it even if my mouth were torn apart
Used with a negative sentence to emphasize that one would never say or reveal something, no matter what. Often followed by 言えない or similar negative verbs.
See also: 口が裂けても言えない
口が裂けても本当のことは言えない。
I wouldn't tell the truth no matter what.
口が裂けても彼の秘密はばらせない。
I could never reveal his secret, no matter what.