After sitting there for a while, Arthur stood up and silently left the garden. His mind was still thinking about the interaction between him and Isla and it only made him feel more and more bitter.
He blamed himself for overstepping his boundaries and for thinking he was already at the level where Isla could tell him everything about her life. She had known the others for years while he was only there for a month or less. There was no base for comparison.
Arthur was a friend, perhaps even a dear friend. But, Isla still didn't see him as someone close enough to her to let him know about her life in depth. Everything Lamenter said was right.
That hit Arthur hard, harder than anything else. These were his very first friends and they didn't fully trust him yet. If that were the case then what could happen if they disagree, argue, or even worse, find themselves in a situation where their interests clash?