how to bind richtextbox to sql server database in windows form application

void fun4explaination(string sql)
       {
           try
           {
               BindingSource ebsource = new BindingSource();
               SqlDataAdapter dae;
               string connectionString = "data source=rakesh-PC;initial catalog=mysoftdb;user id=sa;password=ruhil";
               SqlConnection conne = new SqlConnection(connectionString);
               dae = new SqlDataAdapter(sql, conne);
               conne.Open();
               DataSet dse = new DataSet();
               SqlCommandBuilder commandBuilder = new SqlCommandBuilder(dae);
               dae.Fill(dse, "dictionary");
               ebsource.DataSource = dse.Tables["dictionary"];
               richTextBox4.DataSource = ebsource;                  //problem is here
               richTextBox4.DisplayMember = "explanation";
               richTextBox4.ValueMember = "explanation";
               conne.Close();
           }
           catch (Exception ex)
           {
               MessageBox.Show(ex.Message);
           }
       }