no kidding
US /noʊ ˈkɪd.ɪŋ/
UK /noʊ ˈkɪd.ɪŋ/

1.
sem brincadeira, sério
used to emphasize that what one is saying is true or to express surprise or agreement
:
•
I saw a UFO last night. No kidding!
Eu vi um OVNI ontem à noite. Sem brincadeira!
•
He actually finished the entire marathon. No kidding!
Ele realmente terminou a maratona inteira. Sem brincadeira!