Miraculous, les aventures de Ladybug et Chat Noir belongs to Thomas Astruc.
Mask
In theory, the presence or absence of a mask will never matter; beneath it, the person is the same, because the mask doesn't fulfill the skin's function, that of enclosing the truth of a heart and bristling before the most vehement feeling.
Adrien knows the truth: underneath Ladybug's mask no one but Marinette lies. She, her skin, her heart. However, precisely upon discovering it, Adrien has discovered something else, the most painful thing.
The rule is fulfilled by her, but not by him.
He, who when he hides behind the mask is Chat Noir, feels him like his own skin. Chat is brave, cheerful, full of energy and charisma, attitude and good intentions, but when the mask vanishes, nothing lies beneath it. He's a sad, grey shadow, without strength, without motivation.
When he loses the mask, he loses everything he appreciates of himself.
He loses himself.
Because of that, because he loves her and because he knows he cannot make her happy by being the shadow and not the person, Adrien doesn't hesitate when the most beautiful words reach him:
"I'm sorry, Marinette. I can't be with you."
She seems to catch his grey color when she hears him, to become a reflection of him in the unfair, not in the positive; she breaks, the brightness of her eyes does it, and she nods and goes away in silence, holding back the tears.
Precisely because he loves her is that he cannot accept that "I love you" whispered with the same light that it seems to get out from her, with the mask or without it, when she speaks.
Chat Noir cannot replace Adrien; Adrien cannot be Chat Noir when he doesn't wear the mask.
That's why Adrien, while crying without emitting sound when seeing her leave, knows that he will never deserve her.
.
To my friends, D. and R.