Arthur never expected to fall in love. Especially not with a commoner.

At first he simply respected your knowledge and how good of an advisor you are. Then he started thinking about you all the time. He noticed the way his eyes would search for you or the way his heart beats faster when he sees you.

Arthur’s a king, a ruler. He shouldn't be feeling this way, he cant be. But he is

You're advising him on what you think should be done with an issue in the kingdom as he listens intently