〜に〜ない means "can't very well ~": you could do it, and part of you wants to, but the situation won't let you – someone is watching, it would be rude, you have gone too far to stop. The same verb comes twice, first in the dictionary form with , then in the negative potential.
、。
My boss is still here, so I can't very well go home.
、。
They'd gone to the trouble of inviting me, so I couldn't very well refuse.
。
I couldn't bring myself to tell the truth.
The first verb is the plain dictionary form, and the second is the potential: the point is that you can't, not that you don't.
〜に〜ない or 〜ようにも〜ない
きごう〜 starts from the volitional form, and the obstacle is practical: no money, no trains, a broken leg. 〜に〜ない is held back by circumstances or feelings – what others would think, what you owe them.
、。
The trains stopped, so I couldn't go home even if I wanted to.
、。
Everyone was still working, so I couldn't very well leave.
Set phrases
A handful of these are fixed expressions, and you will meet them more often than new combinations.
、。
Having come this far, there's no backing out now.
。
It's the kind of story you can't really laugh at.
。
I made a mistake so bad I couldn't even cry about it.
。
There are reasons I can't really talk about.
Lingaku