Ingenious and Ingenuous have a little difference of ‘i’ and ‘e’ only but this brings a little difference in their pronunciation and meaning as well.

Ingenious ( pronounce with ‘eee’ sound after ‘g’ ) means cleverly inventive or extremely skillful
His skills led him to invent this ingenious machine.

Ingenuous ( pronounce with ‘a’ sound after ‘g’ and ‘oo’ sound after ‘n’ ) means candid, frank and innocent
Everyone loves the company of an ingenuous person.