The context of my question is the usage of a grammar point from a JLPT 文法 textbook. It is not the grammar point itself that I am asking about, but rather the grammar used to explain the grammar point. Sorry for this complexity.
The textbook explains how to form sentences using the pattern 「〜（の）なら...」:
(Basically, the second line is saying that if ~ is a na-adjective or a noun, for instance 雨, one can have 雨なら, or 雨であるなら, or 雨であるのなら, but NOT 雨のなら.)
My question is this. How to break down the にはならない in bold font in the second line above? I think it could be one (or neither) of the following possibilities:
- Is it just the negative of ...になる, with は in にはならない being there for emphasis? If so, what exactly does になる mean in this context? To become? To be?
- Alternatively, does ならない here mean "must not"? If so, what exactly is the usage of には here?
I would greatly appreciate it if somebody could explain this. Many thanks!