Learn how to say Ingenuousness correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word ingenuous:
(of a person or action) innocent and unsuspecting:
he eyed her with wide, ingenuous eyes
she’s staggeringly ingenuous, or possibly very cunning indeed
late 16th century: from Latin ingenuus literally ‘native, inborn’, from in- ‘into’ + an element related to gignere ‘beget’. The original sense was ‘noble, generous’, giving rise to ‘honourably straightforward, frank’, hence ‘innocently frank’ (late 17th century)