The spaces are coming from the result of the query, so when you manually change it, it is updated again with the value from the binding.
You will need to remove the whitespace inside or prior to the binding.
One way would be to use the Trim() function inside of the SQL statement.
Select TRIM( YourColumn ) FROM YourTable
If you don’t want to do that, you could also create a custom property and bind that to the query result and then use an expression binding with the trim expression on the label