He lifted up her skirt without warning ofcourse she will react that way she's only human. Also in that world their morals is way too high seeing the way the female elves dress and the guys dont break a sweat. Let's not forget he killed his previous maid and not to mention tell her the truth about his incident
She was only acting "bitchy" because obviously, as someone who's new to this world, hasn't encountered any monsters yet, and has no offensive capabilities yet, she was feeling that she would die if she went to the dungeon with them. Which is completely understandable. He was trying to sweet talk her into going, and in the end, used the contract to force her to go anyways ╮(￣▽￣)╭
I do agree on that last bit though. It's annoying that she still puts up with their attitudes.
The girl gets so bitchy with the guy for no reason sometimes when he's just trying to be nice to her, like right here wtf. http://www.mangago.zone/read-manga/a_taste_of_love/hs/hs_chapter-9/26/ Also, I feel like their trying too hard to make scenes that aren't even all that romantic super special. When, in reality, it's just lazy story writing so they can find an excuse to make them into a couple. I mean, they haven't really even gotten to know each other all that well so how could they be falling in love with each other? and why does she keep blushing when they get close to her if she does not like how they're treating her and thinks their annoying and disrespectful towards her?