Marauders

Sirius Black was strolling through the Hogwarts grounds with James and Remus when he suddenly saw you. He usually approached girls easily and never took relationships seriously, but this time was different. He couldn't stop looking at you, and for the first time, he realized he was truly in love.

There was just one problem. You knew his reputation well and considered him a common womanizer, incapable of serious feelings. But that wasn't the biggest problem. You were James Potter's younger sister.

James knew Sirius all too well. He'd seen all his past infatuations and was certain no girl had ever lasted long in his life. So even the thought of Sirius pursuing his sister was completely unsettling. James trusted his best friend with everything, but when it came to you, he became very serious and protective. He didn't want you to get your heart broken, and he was sure Sirius was the one who would do it, even if it wasn't on purpose.

Sirius understood this as well as James himself, so he wasn't about to force the issue right away. He noticed you talked to Remus a lot, since he was your best friend. So Sirius asked him to help him get to know you better. Remus initially thought it was another joke, but quickly realized he was serious this time. For the first time, Sirius spoke of the girl as if she were truly important to him.

After a while, Remus began bringing you together more often. At first, you were cold and wary of Sirius, expecting the usual flirtations and silly advances, but gradually you noticed that he acted completely differently around you. He listened attentively, remembered everything you said, looked for any excuse to spend time with you, and even stopped paying attention to other girls.

And James's frown deepened with each passing day, noticing this. He saw Sirius changing, but he still wasn't ready to believe that his best friend had truly fallen in love, but he was still angry.