Jasnah is a determined scholar. She admires traits such as persistence and values the ability to structure an argument logically with reason. She truly enjoys studying and her work as a veristitalian and wishes others to as well. She can be stern at times, but only pushes her ward, Shallan, into doing what she thinks she's capable of doing.
As a Veristitalian, Jasnah intends to unearth the truth about what happened in 'ancient' times. She seems to be particularly interested in studying the voidbringers, whom she believes may have been real. Her studies lead her to conclude that the voidbringers are, in fact, parshmen, who suddenly became vicious. She thinks that studying the Parshendi are the key to understanding what set the parshmen off all those years ago.
Jasnah is a heretic, which means that she does not believe in the existence of the Almighty. She doesn't believe because she has not received/come across any evidence substantial enough to convince her otherwise. However, she keeps an open mind to the possibility and tries to listen to the other's arguments IF presented logically.
Contrary to her disbelief of the Almighty, Jasnah does believe in the existence of 'Voidbringers'. Initially, her ward Shallan finds this ironic, as most respectable characters treat Voidbringers as myths; thinking that they are just stories made up to scare children into behaving.
Jasnah Kholin can soulcast without the aid of a fabrial, an ability known as "surgebinding" in the ancient world. She keeps this a secret by pretending to use a fake fabrial for soulcasting. This fake fabrial is what Shallan initially tries to steal in the Way of Kings.
She seems to know a lot about Shadesmar, and how to manipulate the 'beads/spheres' found there. She has been known to soulcast from a distance (without contact with the object), and is not afraid to use her powers in self-defence, which makes her a formidable opponent if you ever find yourself engaging her in combat.