His eyes were like the moon, she realised.
Not because of the shape or colour or anything like that.
But because of the sides.
For the moon, there's one side that's always shown, the light side, and you can never see beyond it to see the dark side.
It was the same with his eyes, or at least Chat Noir in general.
There was his happy, light side, which was always shown. And you could never see beyond that, to see the darkness in him.
Unless you knew him, and Ladybug did.
Of course, everyone had their darkness. But you could often see their darkness once in a while, but with Chat Noir...
If you didn't know him personally, you wouldn't even know he had his own darkness.
Being a superhero might be a cause, but Ladybug could tell that there was something... more. Something more personal.
Something she would help him through, even if he was hesistant to ask for help.