It's always tricky to do conclusions.
Basically they are like the end of a conversation with a friend - when you are finishing a long conversation and getting up to go, you usually talk about the future (what you will do or where you will go next, and maybe wish the other person luck with something that you have been talking about). You won't usually suddenly launch into a new topic, because that would mean you would have to sit back down again and have another cup of coffee or whatever.
So in the case of this essay topic - 'Does foreign aid help donor countries more than the recipients?' - you are probably going to just summarize, as you did in the first sentence here:
In conclusion, conflict of interests can arise when aid is provided to a country by another. A potential solution is letting a neutral third party, like the United Nations, handle the aid program.
...and look to the future (as you did above with your UN suggestion) but perhaps give your general opinion, rather than specific new information....
In conclusion, conflict of interests can arise when aid is provided to a country by another. It's unfortunate that when so much help is needed in the world, it often comes with so many strings attached. Perhaps new, neutral systems for delivering aid would solve the problem, but the important thing to make sure is that aid is for the benefit of the recipient, not the donor.
As you can see, I haven't done any better than you with the conclusion!