 Why is Starre hesitant to accept Bob's feelings?
Moments later, they were outside the ship, with star-powdered infinity spread to all sides. Now that he and Queazy had found the asteroid, they were desperate to get it to its destination, for fear that the Saylor brothers might get wind of what was going on, and try to beat them out of their profits. Now they scuffed along the smooth-plane topside of the asteroid, the magnets in their shoes keeping them from stepping off into space. He and Queazy caught up with her on the side of the asteroid they hadn't yet examined. "It's—it's very important that this—this asteroid stay right where it is," she said huskily. There was no asteroid, no girl, no Queazy.
 She feels trapped by her Grandfather's bargain.
 She knows that the wedding has to happen, one way or another.  She doesn't feel the same way about Bob.  She feels trapped by her Grandfather's bargain.  She still cares about Mac, despite all that's happening.