I've done some researches to buy a hotel, why should I need a broker to help me closing the deal?

You may or may not need a broker but you will need a good real estate attorney that has closed Hotel deals before.
The reason to have a real estate broker or a real estate and business broker on your side would be to have someone with a fiduciary responsibility to you, who has industry knowledge and access to current market information that can help you evaluate your best options. They can negotiate with the seller's brokers who could potentially put in tricky terms that benefit their client(s), since their fiduciary responsibility is to their client(s) only no matter how friendly they appear.
If you are buying an the hotel as a business with real estate, some states have separate licensing for business brokerage. The business broker I refer people to in Illinois has a CPA certification along with his business broker license and real estate broker license. I believe anyone looking to open or expand a business needs to carefully pick the players for their corner and plan. Best of Luck.

That was a very good answer. I would add that unless you are a seasoned hotel buyer, you may not know what to look out for and how to negotiate the best deal. I know a few people that think they know all as investors or tenants, but when I ask them if they put in something in the lease or offer to protect themselves, they respond no. You know the old adage, penny wise & dollar foolish. I think that is the case often. My friend works at PKF Consulting in Research in Atlanta, GA. They consult and sell hotels as their primary business. They also have an appraiser area. Please call Robert Mandelbaum for a referral and make sure you tell him that Nancy Gastel sent you! Ask for Charlotte as your appraiser too. Let me know how else I might be able to help.

"Kudos" to the previous answer (John G) I could not have said it better myself, next time I'm in the Aurora Illinois area I'll drop by. JAY H, you got your answer now you indicated three states for where an investment was desired and here in Florida they vary from size and type; many of the "Mom & Pop Motels on the seashore have gone to make way for condos; that is not the case as much today and there are still good opportunities available to a savvey investor/operator.

You are right, you do no need a Broker, however, it is most likely that you or the seller will still pay the commission on the sale of the Hotel. The amount of the commission (%) is set by the Seller, so either, the seller’s broker takes the entire commission or it is split between 2 brokers, (with buyer’s broker) which will be representing your best interest, in essence at no additional cost.

There is a tendency when a buyer is negotiating directly with a seller for things to get off track. By this I mean that there is a likelihood of "you said - I said" type misunderstandings to come up, which can often lead to personal friction between parties who need to negotiate through difficult issues. Your broker not only negotiates on your behalf, he or she will follow a process of written documentation for each specific point of agreement. That removes the risk of you said - I said and allows the parties to work through the issues without additional emotional stress.

A broker or hotel attorney will know how to contract the deal. Are you buying an llc or what is your personal property beds etc. tax libility verse property tax. ???