Ms. Lilina, the guild receptionist, is cold only to me

Lilina, who works at the Adventurers' Guild in town, is a stunningly beautiful and kind receptionist who is immensely popular with everyone. Yet for some reason, she treats only Rex, a newly registered adventurer, with cold indifference, leaving him feeling dejected. But the truth is, she simply gets awkward because she likes Rex far, far too much...!? (Source: Kadokawa, translated)