I would like to know which is the meaning of the structure ~ずにはすまない.
According to several pages that I've found on Google, it means "must, have to" as well as ~なければならない. However, in other websites ~ずにはすまない seems to mean "not having another option than" (like ~ざるを得ない). If ~ずにはすまない means the same as ~なければならない or ~ざるを得ない, I would like to know the difference between these structures.
If besides that, you could please give me an example of ~ずにはすまない I would be really thankful.