applying two fonts for a single word

Don't think of it in terms of a single word. It is two or three sequences of text. Each sequence has a font. You must assign a font to each peice. Each font can be either the same Type Face such as Arial or Times New Roman or a different Type Face. They could vary or not vary by size or other attriutes such as italics. If the two fonts vary just in weight, whether bold or not bold, then they are still two fonts.