Can a guy stop liking a girl within just a week?

In a week time it is enough for a man or a woman to see if they should date and go into a relationship together.Since he has stop he seen something or didn't feel they should continue and has no feelings to stay with her.To me he is an honest man he could have use her for a lot of things but he did the right thing there was no chemistry between them.He will not return and it is time to stop searching the whys and move on to someone new.