The Tyrant's Apprentice (The Stellar Fracture Saga) by Eric Fieldstone

Julie Lorraine, a recently orphaned teenage girl, finds herself chained to a wall in a tiny cell on a remote space station. A masked man who can read thoughts and alter memories claims she has a hidden supernatural potential, which only he is able to unlock. However, his ruthless methods push her to the very limit. Can she afford to trust the two foreign agents he assigns as her tutors? One says occult threats lurk at the edge of reality. The other hides his face behind a menacing helmet but speaks with a sugary voice. To discover the truth, she’ll have to put aside her yearning for love and focus on surviving the tyrant’s brutal trials, which include an intense workout program, combat training, and psychic attacks. Only then can Julie hope to recall her missing past and navigate this maze of lies.