Jacob Black
Jacob Black is a fictional character in the books Twilight, New Moon, Eclipse and Breaking Dawn by Stephenie Meyer. He is described as a Native American of the Quileute tribe in La Push, near Forks, Washington. During New Moon, he undergoes a transformation that enables him to phase into a wolf at will. In the film Twilight, Jacob is played by Taylor Lautner.
Rosalie Hale
Rosalie Lillian Hale is the adopted daughter of Esme and Carlisle, adoptive sister of Edward, Alice, and Jasper, and wife of Emmett. Her physical age is 18, and she was born in 1915 in Rochester, New York, as the daughter of a banker. Rosalie is described as being the most beautiful person in the world, even for a vampire; she is tall, statuesque, and has long, wavy blonde hair.
Relationship between Jacob & Rosalie
Jacob and Rosalie mainly interact during the fourth novel of the Twilight series, Breaking Dawn, in a quite entertaining way. However I feel it is better not to go into the details, so as not to spoil the book for anyone who has not yet read it. :)