I'm only here for the main knights, Ulyseon, and Ruth. The FL is quite frustrating to say ...

She'll get there, but you're reading the wrong kind of manhwa if you want a self-assured confident FL. Here's my defense in response to ur comment:

First, she's not a bum. Yes, it's frustrating to watch her, but considering the era of which the setting is on where women back then had no rights and only considered as property to be married off to give birth, her being a stutterer born from a noble family is seen as a disgrace to her father and other members of the family, which led to abuse both physically and mentally and gave birth to her insecurity to the point she closes herself off from others.

Second, she's not incompetent nor useless. She didn't know much at first probably only because she wasn't given the education a normal noble would receive due to her issue but she's a fast learner, proven by how she handled the renovation and managing of the castle with Ruth's help yes, but she still was able to manage it. Also, she was good at writing before she even came to the castle which is proved by her helping Ruth with the runes before he started teacher her magic for that barrier spell and that Ruth was so impressed with her that he offered to teach her magic Precisely because he saw potential in her.

Third, She's clingy with Riftan because of her insecurity which comes from the setting of women being unprotected if their husband dies at the time to which that while she loves him and wants to help him, she probably has this underlying fear that if he were to die, she would be brought back to her abusive family which she does not want to ever happen and so goes to War with him so she can watch over him or something. Also that fact that she's gained a confidence she's never felt before in her life and wants to show it to her husband.

I don't think she, herself notices how far she's overcome her insecurity to the point that she talks back to the knights without fear and even had the bravery to follow her husband to freaking War! ya'know, where people Can Potentially get Unalive? If she weren't protected by plot armor, she probably would have died already just from the high chance of it happening to extras--especially with how reckless she is.

Lastly, bcuz dang this is long.. Riftan is overprotective because he loves her and only knows that she's a noble lady with assumedly lady education, meaning delicate flowers that grew up to only know how to manage a household and raise a family. He doesn't know much about how she lived so is confused as to why she wants to follow him to War she's never experienced before. It justifies why he's angry at her for sneaking and well... I wouldn't say he's 'controlling'. He gives her a lot of freedom on what she wants to do, ie. learning Magic, riding to War with him up until a certain point even when she herself confessed she's skilled in riding horses, becoming a healer etc.

All in all, this is an extreme case of Misunderstandings from both parties, and would be resolved if FL came out about her past life to which I'm very sure Riftan would storm the castle and empty it out if you get my meaning.. but yea, we take the long way round bcuz FL needs to gain more confidence and admit her part to ML and ML needs to gain more patience and ask his wife the right questions while in the mindset of a knight in a medieval setting. Soooo...

That's my take on this.. ╮(￣▽￣)╭

edit: riding to War with him up until a certain point even when she herself confessed she's [not] skilled in riding horses.

She is Not Skilled in horseback riding.