I hope you are well today and thank you for your questions.
Is it possible to have different fonts in a line of text?
To achieve this you have to develop custom code as described in the following topics.
In Customizer > Styling there are “Additional Font” and “Accent Elements” sections. How are those used? And does it apply to above scenario?
The additional font is applied to the post titles if Post Title field is set to additional font. The accent color is a standard color which applies throughout the site except links, headers and meta colors.