Thanks for the chapter!
Seems like Chenxi is very jealous of Hua Hua's abilities. MC should just explain that his sister had gotten into trouble for sleeping with Xing Lie's son and needs Hua Hua's help to find out more about the Xings so knows how to approach Lie and what to expect if things go south. Since Lie is the mayor and related to the city's #1 cultivationist he wanted to show his worth as a man by handling things without her along with avoiding getting her and the Ye family in trouble, especially considering her directness is more likely to anger Lie than help.
BTW, didn't he ask for a handgun to be able to shoot the Wang-Chuan bullet, why did she bring an assault rifle? Granted an assault rifle can switch from one shot, three shots to fully automatic but he only has one bullet and how is he going to carry it anywhere? At least with a handgun he can carry it concealed so enemies (or at least amateurish ones who don't know what to look for or too arrogant to notice,) don't realize he's got it, get a permit, and be able to move faster and easier since it's small and light. An Assault rifle like that is likely to get confiscated by the police due to being military grade weaponry licensed to big companies not individual civilians, bulky, shows an aggressive stance just brandishing it, only has one special shot for it (unless he can duplicate the Wang Chuan bullet somehow,) and takes practice and training to use properly. It's not like the movies where some newbie can pick it up, handle it with ease and mow all the bad guys down. For starters it's got a strong kick so need to know where to position stock or the kickback could crack or break a rib or bones in collar or shoulder, how to release and lock in a magazine for reloading, how to aim taking into account distance and wind, and also how to compensate for the barrel rising from the kickback from each shot fired lest it slams into his face or expend most of the ammo over the targets instead of at.