How we cite our quotes: (Chapter.Paragraph)
Quote #1
He decided then that he would love her forever no matter what came to pass. It was not so much a matter of deciding as accepting the inevitability of it. It made him feel better, though he felt perturbed, too, worried that this kiss was wrong. But from his point of view, at fourteen years old, their love was entirely unavoidable. It had started on the day they'd clung to his glass box and kissed in the sea, and now it must go on forever. He felt certain of this. He felt certain Hatsue felt the same way. (8.41)
Ishmael's love for Hatsue is intense, long-lasting, and ultimately (when she stops returning, or pretending to return, it) debilitating for him. It also appears to involve a certain amount of denial or just self-involvement on his part, since he is consistently out of touch with how Hatsue is feeling.
Quote #2
He and Hatsue spoke of little things at first, then of the San Piedro fields they'd left behind and the smell of ripening strawberries. He had begun to love her, to love more than just her beauty and grace, and when he saw that in their hearts they shared the same dream he felt a great certainty about her. (11.39)
This is a description of how Kabuo's love for Hatsue grew gradually. It's interesting that his love for her grows on the basis of shared dreams and experience, whereas that doesn't really seem to be the case with Ishmael.
Quote #3
He was twenty yards off when she called his name and asked if he would marry her before leaving. "Why do you want to marry me?" he asked, and her answer came back, "To hold a part of you." She dropped the hoe and walked the twenty yards to hold him in her arms. "It's my character, too," she whispered. "It's my destiny now to love you." (11.42)
Whereas Hatsue felt everything was wrong, wrong, wrong with Ishmael, things with Kabuo are so groovy and right that she feels loving him is "destiny." It's pretty much a night and day comparison between her feelings for the two boyfriends, no?