What is the IMF? Expand it, and then put in brackets IMF after, so people know what you're talking about when you bring it up again.
Don't you think it is impossible to eradicate war since people act egotistically
Are you asking, "Do you think..." or are you asking, "Do not you think"? The second doesn't make any sense. Yoda sound you like.
I realized you're Japanese on your last paragraph, so I was rather confused as to why you specified the Japanese staff. After all, they are not as involved in war as US, so why did you choose them specifically? If you don't want to bring it up in your essay, just say "staff".
war will continue living on the earth
1. War is not alive. Perhaps use a different metaphor?
2. Earth is capitalized.
3. You don't need "the" in front of "Earth".
Since the location of Georgetown, Washington DC, the center of the global politics and excellence of education of international relations provided by The Walsh School of Foreign Service (SFS) match my ideal educational place, I decided to go to The Walsh School of Foreign Service and major in international politics
Georgetown is located in Washington DC, the centre of global politics. The Walsh School of Foreign Service has an excellent international relations program, where I intend to major in international politics.
General note: do not use contractions.