this is something you should probably know, so I am posting this to help Flash beginners
Flash can’t display by default all font style in a TextField. To be able to do that you need to embedd font with every style you plan to use in library separate. In a library menu (you get it when you click icon in Library title top right corner) and click on New Font option. Then you select font, and style you want to embedd and do it for every style you plan to use 
I am repeating myself but that’s good for beginners.
SWF Example
FLA file
