Sara is Setsuna's younger sister, and the object  of his affection. She returns his feelings, and in fact she is a lot like her brother--both of them are very emotional people.  Sara has a lot  more, ah, shall we say 'moral fiber' than Setsuna, however.  She is constantly scolding (and hitting ^_^;) her brother for fighting and various other things.  She is honest, but I think she has a bit more tact than her brother.  I personally like Sara--I think she's funny and cute. ^_^  Plus I _do_ think she and Setsuna make a good couple (yeah, yeah, incest incest ^_^;), though admittedly I wouldn't object too much if she went with Raphael and Setsuna went with Kurai (just 'cause Kurai is so cool).