I actually read that part as iblellin is in love with latte and wants to show arwin that latte is hers.
I cant see Iblellin as having romantic feelings for Latte. For me its more like " You are my friend as long as i am the center of attention, always". Thats the vibe i feel when i see her. Maybe cause she ignores Latte everytime one of the romantic interests gives her attention. Like, completely ignores Latte, i think at first she really liked Latte as a friend, but as soon as she started stealing her attention, well, Iblellin started to get annoyed. But as Iblellin is the " pure and sweet character " She cant just ignore Latte all of a sudden.
Just my opinion, but, i think Ibellin actually lied about asking Arwin to bring Latte to her ( that balcony scene and stuff). Cause Latte did say " You have a really good sight " Or something like that when Arwin could easily tell her apart from the rest. Idk, i feel like she did that cause she didnt like the attention Arwin was giving her and wanted to make Latte realize Arwin would never be interested in her. I DONT KNOW, MY MIND IS A MESS