Make text bold in post list

Hi there,
I would like to know how I can make parts of the text in the autogenerated list of posts bold or italic.

I have a widget which allows me to tag pages as categories.

Here is an example where I want to make the date of the event stand out in bold :
https://www.infomedltd.co.uk/new/?cat=8

If you click through to the page you will see that the date on the text is bold.

Many thanks for any help.
Jack