- 誠まことに恐おそれ入いりますが、その件けんには対応したいおうしかねる。

makoto ni osoreirimasu ga, sono ken ni wa taioushi kaneru.

I'm terribly sorry, but on that matter, I cannot bring myself to accommodate you. formal

- うーん、それはちょっと判断しはんだんしかねるなあ。

uun, sore wa chotto handanshi kaneru naa.

Hmm, that's something I cannot bring myself to judge easily. casual