Hi there, you can use the textbox component to type in specifically which words you want to be in bold and click on bold under the formatting tab and position the rest of the string after those words.
Alternatively, you can create images of the words(with the specific words bolded) and include them in your excel sheet and present them like I assume you are currently doing with your text.
At the components panel, if you click on Stimuli (under Favourites), it the last component. You should be able to see it if you have the newest release (v2021.2.3).
But I do agree with @wakecarter that using images with formatted text is the most straightforward way of accomplishing this.