Sincere Scholar is the head marestress we all wish we had. The knowledge and sheer wisdom she possesses in all areas could give Queen Galaxia a run for her bits.  
She takes her classes and running the Equestrian education department very seriously. The Cheerilee and Ms. Harswhinny components of her will stop at nothing to ensure her students nab the best grades possible and blossom into their utmost potential whilst the sheer showmanship of Trixie makes sure they have fun doing it, to the point where it doesn’t even feel like work with creative and engaging lesson structures. Then of course you have that leading authority and a fair but firm hoof of Spitfire which comes in handy when the students even dare to misbehave as well as making sure her voice is heard in teacher meetings (oh and it comes in handy for some hooves on wonderbolt lectures)
 
However though, recently during the students leading up to their final exams and studying time, many a young colt have become rather focused on another large round bountiful plump form of study in the meantime. Suffice to say that whenever the Headmistress peers back to ensure her students are hard at work, they technically are in the sense. That being the studies of such a plot on the young princess. One thing is for certain…  
Her Harshwhinny and Spitfire components will get the better of her students. A couple laps around the track and some more proper etiquette elective courses should tidy up these rascals whom stare at their large lovely rear.