Hontou ni. ／ Mattaku ne.

　　　　　　　　　　　　      ( translation: That's so true. ) 

Ex.

      1. A : I think they should export this product to America.

          B : Hontou ni ( That's so true ). People would love it. 

　　　2.  A: I can't believe why he made the mistake. 

           B : Mattaku ne( That's so true ). He is the last person to do that.