@givemersspls: Well, much in the same way that detective stories don't go "Who's the last person who's with the victim? You? YOU ARE THE CULPRIT FOR SURE", they don't assume a maid who has shown no prior knowledge of music (or sculpting, for the previous matter) to be THE one to craft these masterpieces.
The way she worded her question to the maestro can also be taken as her knowing who this mysterious musician is, and not that she is the mysterious musician herself.
And in a way, that's the truth, all these skills she's shown are from someone else.
So she can say she's not the one who came up with the finish piece, and she wouldn't be lying in a way.
@XieShu: He wasn't trying to kill her iirc.
Yes he was there holding a bloody sword and with eyes of 0 mercy, which given how the girl's previous family treated her, I don't feel bad about him murdering them.
But on his POV (ch 6) he admit to her being the only royal family member of that empire he had admiration for due to what she did in the short term she's a princess.
And right now, if possible, he plan to make her his wife.
Yes he plan to kill her if she refuse his offer of marriage, because then she's a seed of rebellion (whether she want it or not), but by his own words, that's the last option for him.
So yeah, most likely the typical 'cold-hearted man learn to melt from sun-shine waifu interaction' shoujo development.
He'll keep running into this maid who just happened to be there when something melting the ice in his heart happen.
And she'll keep running into this sad boy at night (because insomnia) when she try to do her help people in secret stuffs.
The official kick start of him seriously falling for her would be the first time she help him get a good sleep.