Play it off coolly

It is an obvious ploy for you to submit to her, one that you're not going to do easily.

It is all too clear that she is trying to get you sexually excited to take advantage of you. So you keep your wits about you and firmly say, "My Lady, I came here to discuss the rumors of your husband's treachery."

Queen Anna sits down on her bed and crosses her legs. "Yes, isn't it lovely how I found evidence of my dead husband's evil schemes to start a rebellion in your nation through his cousin Arch-Duke Franz Jacques to weaken you for his spring invasion?" Queen Anna uncrosss her legs and pauses long enough for you to notice she is not wearing any undergarments before recrossing them in the other direction. “I made sure everyone knew what he had done to ensure they would know you’re the victim in this tragedy.”

You grumble, “How convenient of you to blame your husband for your misdeeds.”

Queen raised her fan in front of her face. “I have no clue what you are talking about unless you are saying that my dead husband did not do the things I said he did. But that would be very bad for you because they are the only justification for your actions.”

She is right; she has you trapped. No one has ever heard of a Queen's influence extending outside her borders. If you tried to fight her story, no one would believe you. “You truly are the most wicked of a woman.”

Queen Anna laughed. “You don't really mean that, considering I just made you so much more powerful.”

“And what to stop me from using that power to remove you right here and now?”

Queen Anna doesn't even flinch as she calmly says, “You could do that, but it is my duty to warn you that on my ****, the world will learn another version of what happened. One that casts you in a much different light. Let's just say our secret night visit will be made known. So you could kill me and become the **** villain to everyone, or you could take my hand as repayment for what my husband attempts to do, and in a few months, I will give birth to our secret love child, and then we can start working on its younger sibling while we work to make you even more powerful.”

As she waits for you, smiling, you consider what to do. You can kill her, and in effect, killing your unborn child. If what she say is true, your reputation will be tarnished, and you may end up having to fight against insurrection against your rule. The second option is to marry Queen Anna and make her your queen. While seemingly a safer choice, there's a very chance she will engage in a lot of shenanigans in your court, possibly harming your mother and the rest of your people in order to solidify her control over you.