You weren't heartless - you were just careless. That's how you always have been. Until you moved in Paris.
You didn't think that people would start seeing you as a third superhero, after helping Ladybug and Chat Noir many times.
You also didn't think that Adrien Agreste would fall in love with you.
And you didn't think that you would fall in love with Chat Noir... Without knowing that Adrien and Chat Noir were the same person.