expression
no matter what; after all; in the end
Emphasizes that a statement holds true regardless of circumstances or objections. Often used to reinforce a reason or conclusion. Colloquial.
See also: なんてったって
なんといったって、彼はまだ子供だから、そんな責任は負えないよ。
No matter what you say, he's still a child, so he can't take on that kind of responsibility.
なんといったって、ここが一番落ち着く。
After all, this is the most relaxing place.