For me, I believe that Mona Lisa's smile represents an enigmatic smile. Her smile shows a puzzle. Her smile is very difficult to explain. The mood is very hard to think about. That's why for me, she portrays an enigmatic smile. I think her smile is pretty impressive. It seems to be scary.
I appreciate how the artist thought of having a puzzle in the art. But for me, I would say that the cause of her enigmatic smile is because of the lack of her eyebrows. It looks like her eyebrows changed her facial expression. This means that our eyebrows affects a lot our facial expressions.
Aside from having an enigmatic smile, her eyes. It somehow adds a change to her facial expression. It's hard to identify whether her eyes are happy or not. Me , I can't even understand her facial expressions. But even though, I truly appreciate the art. The puzzle is such a good idea. The enigmatic smile was just a very good thing that made the Mona Lisa painting mysterious and famous. Without the question in the smile, the painting would not be famous. The smile gives a lot of value in the painting.