Naomi is an idealist. Passionate, political and principled, she's the only one who still believes in anything.
Throughout the third and fourth series, Naomi's sexual orientation is left ambiguous; after firmly maintaining she is straight, she later confesses to Effy and Emily, on separate occasions, that she is unsure. In the last episode of Series 4, Naomi reveals that she is in fact a lesbian, as she said that she fell in love with Emily when they were younger, but was afraid of Emily's effect on her, so she slept with boys to try to get rid of her feelings for Emily.
Much of the third series is about Naomi dealing with her feelings for Emily and questioning her sexuality. Up until Pandora, Naomi maintains that she is straight and does not have feelings for Emily, who she knows is in love with her. However, in Naomi, they share their first sexual experience. By the end of the series they both come out publicly as a couple.
Much of the fourth series deals with Emily and Naomi having problems with their relationship, mostly due to Naomi cheating on Emily while also having contrasting plans on whether they should go to University right after graduating or not. By Everyone, their relationship is on the rocks, but Naomi finally reveals her true feelings: that she had always loved Emily and that she is done running, and presents to her two tickets to travel after graduation, and thus she and Emily reunite.
Naomi's profile on E4's official Skins website.