How can i can i convince the consular officer of the us emby that i am going back home after uni. at the US

you need to sort of prove to them that you have a job lined up at home in your field of study. If you or your family have ets (home, land, businesses) that is something they need to hear because they worry about people that don't have anything to go back to...they think those are more likely to stay in US illegally. Good luck, they are being real sticklers (to use a nice term) now!!!!