If you introduce yourself as a broker, you may see eyes dart back and forth as the person you are talking to looks for an excuse to escape. "Broker" in almost any context means "sales person". The exception is when someone is already interested in buying or when they have something to sell.
Introducing and branding yourself as a broker is similar to branding yourself a doctor. Doctors are more respected. Both "broker" and "doctor" are generalized labels which leaves more questions than answers.
In the new world of data and media, everything is indexed, including your services. When you dig deeper into Google's keyword ideas tool and ask for suggestions for terms related to "broker", there are many ideas provided: