Despite her chronological age, Vanille has the physical appearance of a nineteen year-old. She wears her bright red hair tied back in curled pigtails. She has striking green eyes, and both of her ears are pierced, adorned with small silver hoop earrings. She wears a light pink halter top, a short orange and yellow skirt, along with yellow boots. She also wears a fur pelt around her waist, which she uses to attach her weapon when not using it; according to Dengeki PS3 magazine, it is made from a bear she defeated herself. Her wrists are adorned with numerous bracelets, and she wears three beaded necklaces, along with an assortment of beads attached to various parts of her clothing. Her outfit is apparently inspired by the traditional clothes of the Namibian Himba women, while her facial appearance resembles the stereotypical Irish Celtic people (red hair and green eyes). Vanille's l'Cie brand is located on her upper left thigh, and remains hidden beneath her skirt most of the time.
At a first glance, Vanille seems to have a child-like innocence, akin to that of a younger child. Vanille also cares deeply for Fang; she constantly worries for her, and does not like being away from her. Vanille also seems tougher than she appears to be since she was able to kill a bear alone. Throughout the game, Vanille is shown to be caring, considerate, and at times, somewhat stubborn. Her caring side is first shown when she does not hesitate to comfort Hope Estheim after he loses his mother, while her stubbornness is evident when Hope questions her intelligence and whenever Sazh treats her like a little kid. She mostly appears to be happy and cheerful when, truthfully, she is afraid. She usually tries to cope with her fears by "closing her eyes and losing herself in happier days".
In Final Fantasy XIII Episode Zero -Promise-, Fang describes Vanille to be careless at times, naive, a crybaby, a scaredy-cat but also curious about everything. Her curiosity is evident by how she wants to explore her surroundings no matter what others might think. Fang also says that she laughs a lot and is kind to everyone. Vanille also tends to remain positive in situations that others would deem hopeless, and tries to see the brighter side of things. Behind her cheerfulness, Vanille hides a fair amount of maturity fitting someone her age.
Despite all of her positive qualities, she is a very emotional person, easily driven to tears whenever things become too much for her to handle. Even though she has good intentions for her actions and lies, she uses her bubbly personality to hide the overwhelming guilt she feels for affecting and ruining the lives of countless innocent people. Over the course of the game, Vanille learns to stop running away from her fate as a l'Cie, and fight for what she believes in.