Complex sentence: Not sure how to deal with his advances, Sayoko points out that he already has Belldandy, however, he claims he does not care for her--though, in his mind he knows he does.
Split into simpler sentences: Not sure how to deal with his advances, Sayoko points out that he already has Belldandy. However, he claims he does not care for her, though in his mind, he knows he does.