Where are you trying to show Bold and Not Bold? On a report? Form? I need to do it quite a bit in reports and the way I do it is by using two controls. One control shows the unbolded text with several spaces for the bold text. THen I add another text box/label with the bold text and put it on top of the first one. The background needs to be Transparent and you will need to micro adjust (Ctrl-Arrow Keys) to line it up properly. But it usually works fine.
Problems arise when the bold text is variable text. When that happens you will need to get creative. Put the bold at the end of a sentence in a paragraph (as an example). But sometimes it just won't work. If you provide more details I might be able to give specific details.
Make a label control with a small phrase.
Make a label control with one word from that phrase.
Overlap the single word label on the other label, slightly offsetting it.
The one single word now appears bold.
But if you want to bold some data, the simple answer is... No.