I think in this chapter Bibi already knows Amy likes her and is treating Amy like her pet (gives Amy the cookie and is happy to see her take it, kicks Amy into the sea to see if she gets angry at Bibi for treating her badly, is happy when Amy does not try to kick her back because she knows Bibi won't like it). She enjoys the idea of Amy liking her so much that she finds her reflection in Amy's eyes beautiful and leans to kiss her only to be rejected, which hurts her but her love for Amy grows nevertheless (cookie jar at the bottom increases in number)