Scarlet is mysterious. She has a certain allure that gets everyone talking. When you see her, you immediately want her to be your best friend, but you're also intimidated to talk to her because she is so cool. A lot of people presume that they can get overly friendly with Scarlet. She'll usually play along, keep it superficial, and use it to her advantage.
Scarlet is willing to open up and get real, but it's gonna take a lot of work and time to prove to her that she can trust you. After all, literally everyone wants to be her best friend, what makes you special?