timing belt been fixed?

If a car has had a new timing belt and new valves etc is it still reliable and ok.We have got chance of a cheap car but it has had this work done ,as the old timing belt went completely damaging other parts as well.It has now done 3000 miles on the new one and the owner tells us it is as good as new but we`re not sure. Other than that the car is a real bargain but is this the reason why? My husband has to travel quite a way on motorway for work so we need to make sure its not going to blow up or anything daft. It is on a r plate and only done 88k which does not seem like lot of mileage for its age and everything about it is in very good con. It`s just this bit that is worrying us.Hope you can help ,as you have probably guessed we`re no car experts. We don`t have much money to spend on one so need to make sure what we do buy is not going to let us down.