Real Estate Law covers an extensive legal area
Real estate professionals and transactions are governed by a combination of state statutes and common law.
Most people in sales positions are not subject to the constraints that apply to folk who are involved with the brokering and leasing of real estate. The clerk in a store, the salesperson on a car lot, only need product knowledge and skill in relating to customers.
It is when the type of transaction has a high degree of financial and personal significance that the public interest requires specifically regulated conduct by a government agency. Medical professionals, financial advisors and securities salespeople, real estate sales and leasing agents, and even cosmetologists must show evidence, prior to receiving a license to practice, of specific training in law and public policy that governs their professions. And while licensed, these licensees are subject to oversight and disciplinary process.
Regulation of professions generally is a State, not a Federal responsibility. As to real estate licensees, the Real Estate Commission [link to page below] establishes educational requirements, manages licensing, investigates and disciplines misconduct, and oversees a fund to compensate victims. See the page linked in this paragraph for details.
Separately from legal oversight, most professions have membership associations that require members to adhere to codes of conduct that can go considerably beyond requirements of applicable law. That organization for the real estate profession is the National Association of Realtors (NAR). A member of the association is a Realtor®. [Link to Board of Realtors page] The page linked to this paragraph describes Realtor® professional responsibilities, as they apply to the public.