Itsuki is the one that really cares about Seto, that's why she came back to Japan, after all. But, she's using their childhood friendship as a pretense to be near him, and sending some mixed signals. (I'm just a friend / I love you) Seto should realize, especially after the hurting her feelings incident, and feeling so bad when he thought she left. But... typical shounen insecurity and boneheadedness means he doesn't understand.
Itsuki cares enough, that she gives up her trip she really wants to take with him, so he can be happy taking a trip with Iori. I hope Itsuki is rewarded for caring so much.
