得ない

Usage

Used to express the fact that "can't do -" or "there's no possibility to"

V ~~ます~~ + 得ない

あの人が結婚したって本当！？え～！あり得ないよ！ Is it true that he got married? No way! It's not possible!

あの真面目な彼が犯人？そんなことはあり得ない You think someone as earnest as him is the culprit? That's unbelievable..