In the Emoji and Symbol palette (control+command+Space), one can visit the upper-left of the toolbar, and click the gear selector to Customize list... , and select Musical Symbols, which will appear in the left column of categories. Short of a dedicated music font, this is as good as it gets.
You can directly insert these musical characters into the Pages document at the insertion beam location by double-clicking them in the above character palette.
Beyond this, you will need Sibelius, or the open-source Lilypond. In either case, a single PDF sheet of music can be dropped and scaled into Pages. Lilypond (wiki) creates an input file to LaTeX which can generate a mixed text and score as PDF. Example of this here.