Beginner

it's too naive naïve to think that someone is approached out of real feelings

I agree

The context you're missing is that both used each other's first name when they were by themselves. That shows a high degree of closeness and friendship even if they weren't dating. That's why their current relationship of superior and subordinate is so awkward because they used to be close peers. You can tell the significance of using a first name by the last page when the guy accidentally used her first name.