As if Trixie needed any more confidence but when fused with Ms Harshwinny she basically expels it; at least she has been granted a much more level head so she is able to use it in a way that benefits society, a guidance counsellor of sorts, who's words also come from a place of experience in Trixie earning quite a few lessons of her own prior to fusing. Her advice may appear blunt and cruel to those who are sensitive to self criticism but she gives it only to benefit and improve the pony in question (I mean she probably does get a kick of pointing out ponies's flaws, but the point still stands)

She has called RT out many a time when her immaturity comes to fruition and although she has been brought to tears a few times, she is a much stronger and mature mare because of it. Maybe these interactions and Strict's investments in Tashie's personal growth are why she trusts this mare completely and has an un-explainable fondness for her even after becoming Sincere Scholar who has toned back her brutality a little bit with the aid of componant Cheerilee.

Strict Talent does have a soft center though underneath her somewhat forboding personality, often being seen using her street magic to entertain and enthrall fillies and colts and is a personal tutor to anypony looking to pursue stage magic either as a hobby or a cutie mark call and can teach them a thing or too about confidence, overcoming ones fears and developing a stage presence.