She wasn't sure what sparked it exactly, just one day, she was looking up, watching Ladybug during an Akuma battle while ducked for cover, and something about her lit up familiarity in her chest. Ladybug had that sparkle in her blue eyes that was hard to mistake and that walk that while not stumbling, not sleepy, not distracted or dazed, was all Marinette and yet she couldn't be.
All of Marinette's excuses out of nowhere came to her mind, and yet Sabine prided herself on being able to tell a lie from the truth when it came from her daughter. Marinette hated lies, hated liars, and so she'd avoided it for the most part while growing up and her heart, she wore on her sleeve, easy enough to spot.
Sabine had known this about her for as long as she could remember and knew so much more. She didn't tend to miss the little details about her daughter; she paid attention to her, encouraged her, worried about her, and supported her. She wanted to always be the kind of parent that made her daughter so, so grateful for all that she'd done, every sacrifice, because she wanted her daughter to be her best self and keep working towards her dreams.
Sabine couldn't see the rigid professionalism in Marinette who still tended to stress to extremes while working on a project that had a deadline though she still pushed herself as much as she could towards it. Marinette was emotional and while working for the bakery, she was usually easier on herself, and in that way, Sabine could almost see that professionalism from the baking side of Marinette in Ladybug, but it couldn't, could it?
Sabine hated the idea of her daughter fighting crime for the sake of all the worry that made her feel sick, for the way it made her realize how short and precious her daughter's life could be, and yet, if it was true, she loved that her daughter understood sacrifice and had compassion for the city of Paris.
It both made Sabine proud and terrified her. Most mothers didn't have to face the fact that their daughters could be risking their lives or superheroes of Paris or whatever, and yet Sabine wondered if she was one of the few. Someone had to be the mother of Ladybug, and if it was Sabine, she never, ever wanted to let her daughter down or make her choose which identity mattered more.
Family meant a great deal to Sabine and so did love, and so she never wanted to come between a hero and her family, those that she returned home to. It was easy in a way to see similarities; Ladybug had always seemed like a teenager, Marinette seemed to find her dad to be a true superhero over herself, and yet Sabine could almost see it.
Marinette had never been a quitter, always eager to work past herself and become better through it, and yet insecurity and fear could rattle her cages and leave her afraid to move on. Her heart could make the decisions that her mind and fear would not let her make.
Even if Sabine was wrong, she was proud of her daughter anyway.