야말로

This precisely; the real thing

It singles out the word in front of it as the genuine, definitive case: this is true hipness, this really is the essence of a rural vacation, this is a proper American experience. Attached to a time word it means this time for sure, as in the caption promising that this time it really is the end. Attached to a person it produces the polite deflection in the line meaning no, I am the one who should be thanking you.

Register: emphatic but normal in speech