If the date and time is stored as datetime in the database, you don't have to convert it to a string and then back to a date.
The Date type is actually a double (or was it single?), representing the number of days since year 1900 (or was it 0?). The time is the fraction part of the number.
You can just add the date and time together to get a Date variable with them both.
startDate = rsDate("startDate") + rsDate("startTime")
startDate = CDate(rsDate("startDate"))