Rianne is one of three friends Aislinn has at Bishop OC. Like Leslie, she is flirtatious, outspoken and is inclined to rebel (or work against) the stereotype of attending a Catholic High School. For example, as soon as she exits school, she pulls off her blazer AND unbuttons her blouse. This is more show than reality however. Keenan says of Rianne, "she smelled like innocence to him, untouched and sweet" which is at odds with her attitude. To hear Rianne talk, however, she knows everything there is to know about sex and boys.

Of the three friends, Rianne seems most interested in seeing Keenan succeed with Aislinn -- possibly because she has a crush on him herself. By offering Keenan helpful advice about Aislinn, she has a reason to put herself into his company.

At the same time, when Rianne runs into Keenan after he and Aislinn attended the fair, she confides to him she thinks her friend needs to have fun. This appears to be the reason she's been encouraging her to go out him. Rianne's comment to Keenan, "I think you'll be good for her," inspires Keenan to consider, for the first time, if he would, in fact, be good for Aislinn. He concludes he won't be; given all that he expects of her; all that she'll be asked to do.