She is tall, with brown skin and black hair.
Rosara is not very strong in the One Power. Her level of strength is described by "The Wheel of Time Companion" as 32(20) which is a middle/low level in Aes Sedai hierarchy. With this level of strength she is unable to open alone a suitable gateway to Travel.
Rosara was one of the sisters in Cadsuane's group in Cairhien. When Cadsuane went to Far Madding in search of Rand, she left Rosara and other sisters to keep an eye to the situation there, under the leadership of Samitsu.