Hi Just joined the community, and was also looking for the sans-serif font, found the following, and although it seems to be about OSX, it still seems relevant for win10.
Web page
https://inkscape.org/en/~su_v/%E2%98%85notes+6Default font (sans-serif)
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Current settings differ from Inkscape 0.48.x - the list of fallbacks for
the generic 'sans-serif' font has been modified to match what
(presumably) browsers on OS X use:
<alias>
<family>sans-serif</family>
<prefer>
<family>Helvetica</family>
<family>Arial</family>
<family>Lucida Grande</family>
<family>Verdana</family>
</prefer>
</alias>
This has the side-effect that SVG files with text likely render
differently in the osxmenu-based package compared to Inkscape 0.48.2
(X11) and earlier 0.48.4 RC packages (Quartz). I'm not sure what
would be the better default... (same in Inkscape independent of
platform/packaging, or same as in other SVG viewers on the
specific platform).
My win 10 doesn't have Helvetica font so the next default is Arial, which matches perfectly
I know this is late but it may assist future queries, Rgds Graham