in this context, i would say 'think' implies you're not very sure, but 'believe' would mean you are a little more confident. 'believe' would be when you have faith in its happening. whereas 'think' would mostly tend towards logical thinking.
the southern african developing countries have made a free trade agreement. my question is how can we ensure that this agreement benefits the people in the fight against poverty. this is the topic of an essay that i have to do, any help would be very appreciated.