When a hiring manager called you back and said they want to hire you, is that for sure?

Two weeks ago I applied for a job, and went to the interview.Then in the first week after the interview they did not call me; and on the second week, I suddenly got the call form the hiring manager, he said they want to hire me, but they are now working on the new schedule for the employees, he also said that he will call me back about one week from now after everything is figure out.
I have been only went to two interviews, which don't have too much experience. I'm not sure if that's means they will for sure to hire me(I did not sign any paper yet)? or they probably will change their mind? can someone help to answer my question?
Asked Aug 02, 2014

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