I haven't received any offer yet for my Fall 2017 enrollment. But one of the professors in a school recently interviewed me. He seemed to be satisfied with my background and invited me to join him. He had experiences in industries and as a researcher in college. But since he is relatively new on his current position, he does not have funds (which means I will have to pay full MS tuition myself). He seems very nice and enthusiastic. He sent me some related publications and asked me to respond him ASAP (preferably in a week). However, I am waiting for 5 other schools' decisions and I don't think they'll arrive in a week. My answer to him was that I would be VERY likely to accept the offer (which is true) but I do need some extra time to wait for other decisions. I feel that, if I reject the offer at the end of the day, it would be like me cheating him. He asked me to decide whether I am interested in the program in a week but I honestly DON'T know unless I have a couple of other decisions in hand.
Right now I have his email attaching some papers on the research topics. I don't even know what and when should I respond him. I feel rude if I don't reply him after a week.
What would you do if you were me?(Sorry for my bad writing as an international student.)