She needs to be more flexible in her thinking. She's worried about ending up fighting against the prince. But he seems to want to be close to her--so why not go with that? If she ends up, like, the prince's most trusted advisor then she won't have to fight him, will she? Sure, he's a pacifist who doesn't want war. But that doesn't preclude weapons research--to the contrary, she can be the strength that means he doesn't need to go to war. In negotiations, he'd just be like "We have so far only demonstrated Astrid-sama's capabilities in limited ways. If you persist in threatening or go through with invasion plans, we will be forced to unleash her full capabilities. You do not want that to happen. Alternatively, we have a nice trade treaty prepared . . ."