That smiling face proves Koichi's integrity, eh?
The prince of this country is a very terrible man who kills his citizens with a smile.
This smiling, lovely guy with me is Koichi.
A laughing face is a smiling face (or just a smile!). 笑顔s all around!
The reading for this word won't make you smile, though. You were smiling, but then you heard about the reading of this kanji. It made you yell out "EH??" (え). Just watch out for the rendaku of かお to がお.