Miami’s top real-estate agent, Dina Goldentayer, sold $750 million worth of real estate in 2021. The 39-year-old agent sells mansions and record-setting properties to big names. She breaks down how she’s dealing with the high demand for Florida real estate. In real estate, the numbers speak for themselves, and the Miami real-estate agent Dina Goldentayer’s numbers speak loudly. Last year alone, the Douglas Elliman broker amassed $750 million in home sales — making her the No. 1 individual agent in Miami by sales volume, according to RealTrends. Goldentayer, 39, kicked off her career in 2005, when she moved to Florida from Maryland, where she studied government and politics. Now, she’s…