Go see Libitina

"Then I will go see her."

"But Your Majesty..."

"The fact that my brother tells me to see her means she knows something."

"Then at least let us issue a summon for her to appear at the court." What your chancellor left out from his sentence is 'where it is safe.'

"No. They wouldn't work. My father did that a few times but she never did. I don't think she cares for my position."

Your father had many knights under his command but he was still wary of her, a single woman, so that is something you should learn to respect that as well.

You were there when it happened. It was in the the same court where you're in right now. You saw your father, sitting on the same chair you're currently sitting, tried to get the guards to arrest her but couldn't. The guards remained in their places as Libitina deigned to not give them any of her time, and instead looking at your father listing out her wrong doings. When he is finished, she merely asked for any proof or witness. When he couldn't, she told him to get them before wasting everyone's time before walking out of the place and subsequently left the castle.

Since then, your father tried to get her to meet him but she never did, replying that it is he who must made the courtesy call on her if he wants something since she was done with him.

"Let the knights escort you."

"No. She is but of one woman." you say, recalling her saying something similar in a sneering manner to your father. "I will go alone."