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

1.
non scherzo, davvero
used to emphasize that what one is saying is true or to express surprise or agreement
:
•
I saw a UFO last night. No kidding!
Ho visto un UFO la scorsa notte. Non scherzo!
•
He actually finished the entire marathon. No kidding!
Ha davvero finito l'intera maratona. Non scherzo!