What are the most needed skills for a successful negotiator in sales?

A negotiator, in order to be defined as such, must have a background in psychology and sociology. These studies allow the negotiator to to understand the customer, giving the negotiator the ability to modulate his speech during the dialogue. Modulate and dissimulate, in my opinion, are the two most important skills. Answering, "patience and persuasion" would mean to simplify, or not fully understand, the negotiator job.

Dear Mr.Danilo

Thanks for your perpective,however I have something to add here:

I believe a Professional Sales person doesn't need a degree in Psychology or Sociology to attain Negotiation Skills.He/She over the period of time deffinitely acquires the skill of a good negotiator and gets to know during sales dialog with the customer how to negotiate feels the customers pulse gets to know the customers buying need and justifies successful Negotiation