Does "sore wa nanimonai" and "nani demo arimasen" have the same meaning? (Its' nothing?) (no worrie
I don't want to use diajobu desu or kamaimasen

Question

Does "sore wa nanimonai" and "nani demo arimasen" have the same meaning?  (Its' nothing?) (no worrie
I don't want to use diajobu desu or kamaimasen

Answer

I think "sore wa nanimonai" does not make sense; it literally means "It is that there is nothing". "Nani-mo" and "Nan-de-mo" have a larger difference than it looks like.

I can understand "nani demo arimasen" 
but it is not "nani demo " but "nan demo".
It should be ""nandemo arimasen"

Answer

I think the difference between them is that the second one is more formal, but you could also say "dou itashimashite"

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