Woo~
Grahm came back and reassured Louisa's anxieties (and went for exactly what he wanted) at full strength. And unlike the Maid story, Louisa is actually happy about his advances, even if she's feeling overwhelmed at the moment. Even better, she's thinking about telling him her secret, which is an honesty I appreciate in romance.
I think the "fiance" thing and that final panel implies that the hero has some past memories himself, which would be an interesting development. If so, Louisa should definitely demand an explanation from him. In fact, she should do so anyway just because he hasn't done anything to get his party members off his back despite apparently being engaged.
The mage and cleric reacting like clingy harem members was as expected. Them talking her down for being a commoner, though was...interesting. So far, they're not being egregiously annoying, but we'll see how things progress from here. I'm kinda hoping to see her shut them both the fuck down at some point. She should have the pent-up emotion and life-experience to do so.
The prince being in love with the mage seems to be a plotline too, so that's neat.
I'm personally a little worried about that last panel. He didn't get possessed by the Demon Lord or something, did he?