Please Stepdad? I Never Ask For Anything!

I have a stepdaughter who excels academically, possessing innate intelligence and great promise. As her educator in one of her classes, I play a significant role in her life. Despite my understanding of her imperfections, she hasn't performed to her usual standard this semester as she nears graduation.
I believe she's been slacking off, opting for an easier path towards completion. Although I strive for her success, she feels embarrassed about potentially attending summer school. Witnessing her self-degradation pains me, as she underestimates her capabilities.
My attempts to reassure her have been met with resistance, showcasing her stubbornness akin to her mother's. To aid her academic progress, I've suggested extra study sessions after classes. I'm confronted with a dilemma as she pleads for a passing grade, appealing to my emotions with her vulnerable gaze.
Succumbing to her requests is challenging, knowing it isn't in her best interest. Despite my efforts to guide her, my daughter manipulates the situation, leveraging her charm to sway my decisions. Despite promising a passing grade in exchange for secrecy, she succeeds in influencing me, blurring the boundaries of our familial relationship.