Assessments have no direct connection to the eventual selling price of a home. A great local agent will look at the most recent sales of the most comparable homes to set a range. The marketing efforts, preparation and condition of the home and skill of your agent will determine the eventual price.
Values from here and other sites are not reliable either. An appraiser will look back at a what has sold, but their work won't be accepted by a buyer's lender and another appraiser will have different data and likely come to a different conclusion.
To determine the current market value of your home, ask two or three agents for a market analysis and see what they recommend.