Fixed Length Derived Field

Please give an example of starting data, expected output, and actual output. What do you see in ReportSmith, and then what do you see in Excel.

Derived field: RTRIM("PS_PERSONAL_DATA"."NAME",30)
My Starting data is: Smith,Wendy L
My expected output is: Smith,Wendy L (with spaces after the L that would total 30 in length. If the name is longer than 30 it should cut off the name at 30)
My Actual output is: Smith,Wendy L (then when I save it to txt it tabs to the next field which starts the address (which will also need the same derived field)).
In Reportsmith I just see the data, I don't see that the spaces are there.
In Excel the columns are there, but I am not seeing the spaces. When I click in the field and go to the end of the name, it stops, there are no spaces. When I save it without retaining format and pull it up in hex editor I see the spaces, but they seem to be varying with the number of spaces
Thanks!!!!

I am now wondering if I should be using a Length function instead of a RTRIM. Does anyone have any input on that?
Thanks!