expression
in all conscience; in honour; in duty bound
Fixed adverbial phrase used almost exclusively with negative verbs to express that one cannot do something out of a sense of moral obligation, decency, or social duty. Often translated as 'cannot in good conscience' or 'cannot bring oneself to'.
義理にもそんなことは言えない。
I can't say such a thing in all conscience.
彼の頼みを義理にも断れなかった。
I couldn't refuse his request out of a sense of duty.