Thanks for the chapter!
She does have a point in him being rather rude. His anger should be directed towards his grandmother for making the marriage contract, not with her who's been polite and trying to get to know him. Granted she is being rude too insisting on following the contract without talking it over with him or acting like this is an arranged noble marriage where the family decides everything and the kids are to meekly obey with no choice in the matter, but she is being considerate in not tattling about his being angry or tearing up the contract to his grandmother. So while has earned some harsh words I think a beat down is a bit extreme as MC hasn't tried calmly explaining his POV and talking her out of it first. Frankly with his teenage attitude and the world view of genders I doubt there's a woman on that world who would go along with what he says and likely either get angry and/or give him a spanking for his attitude.
As for the TL note she's not being turned on, and is obviously reaching for something tucked away in her cleavage. After all, in Grenadier the MC Tendo Rushana keeps a whole bunch of bullets there that she bounces up to speed up reloading and her acquaintance Oona had a gun stowed there. Question is, is it gun with the special bullets, a communication device, or something else? In any case he's probably just reached the top of her suspect list for the death of her purple robed coworker by pulling the sword out. MC really needs to learn more on getting an accurate read on people's abilities and fighting skills rather than assuming he'll be able to floor them easily and acting like a rebellious teenager. If he didn't have one of those pills to boost his strength he'd have lost that arm wrestling match to Tang, and now he's fighting someone who isn't a desk bound corrupt elite but a woman trained and experienced in fighting cultivators. Speaking of which, you'd think with all the exercise taking down cultivators she'd be more fit like the purple robe rather than chubby. Unless she's like Choji in Naruto who can use that excess fat as energy or abilities are based on having it.