@KazumaLee94
I wasn’t trolling. I simply misunderstood the panels. I had an impression she wasn’t going to tell him she had the chocolate and in my head a few reasons why she wouldn’t tell him about it (like that it was for another boy) came up.
When I saw your reply I reread this chapter...
So the box:
1) Someone else gave her that box. She just doesn’t want him to see. She probably meant to mock him with it but when she realized how jealous she got over him she didn’t want to put him through that.
2) like above only she bought it herself for herself.