OK, I figured it out myself. A function's return value is its own name.

The following code works...

Public Function FetchWages(emp_code, search_date)

Workbooks("Misthoi.xls").Activate
Worksheets("Data").Activate
evaluate_string = "MATCH(1,(R_CODES=" & emp_code & ")*(R_FROM<=" &
search_date & ")*(R_TO =" & search_date & "),0)"
table_row = Evaluate(evaluate_string)

If IsNumeric(table_row) Then
FetchWages = Application.Index(Range("D_WAGES"), table_row, 7)
Else
FetchWages = 0
End If

End Function