Complex sentence: She is one of the Top students of Class B who is very much admired and respected, unlike most students who despised the lower class, she is basically down to earth and doesn't mind being friends with some of them like Kikuyou and Ayanokouji.
Split into simpler sentences: She is one of the Top students of Class B who is very much admired and respected. However, unlike most other students who despise students from the lower classes, she is basically down to earth and doesn't mind being friends with some of them like Kikuyou and Ayanokouji.