Anyone notice that he recognized that it wasn't the same as the other handkerchiefs? Jayna said that she had her maid do the handiwork, yet Cassiel noticed there to be a difference.
You don't notice these things unless you take careful looks at the previous handkerchiefs.
Cassiel's feelings for Jayna are real.
But... I think in this story, the damage is already done. She's gonna end up with that blond prince, while at best, she can only maintain a platonic relationship. If she could forget her future past, she could have been with Cassiel, but because of Angela, Cassiel and Jayna can never be together.