Why does Namine and Kairi look different

Here is the REAL answer: As you all know, Kairi is not supposed to have a nobody since she never turned into a heartless(because her heart is pure light). But, when Sora sacrificed himself he had 3 hearts inside of him:Ventus's heart, Kairi's heart and his own heart. Since he turned into a heartless (and the 2 other hearts we're inside him) 2 nobodies we're created: Roxas(Sora's nobody) and Naminé(Kairi's nobody). As for Ventus's nobody, he wasn't created because Ventus's heart went inside Roxas. That's why Naminé shares a special connection with Sora while she's Kairi's nobody, it is because she was born from both Kairi and Sora.