When I opened the SVG file, the line was underneath the blue book. I move the line on top, and saved as WMF. I wasn't sure if I could open a WMF file, but when I double-clicked, MS Paint opened it. And the line is showing on top of the book.
Oh, oops. Your first message talked about WMF, but I just realized your 2nd message is about EMF. I don't know if I can even open an EMF file outside of Inkscape..... But let's see....
Ok, again, the EMF in Inkscape has the line under the book. So I moved it on top of the book, and saved.
Oh good, LibreOffice opened it! And it looks correct there too.
I guess that somehow, when you saved the WMF, the line was under the book. It's hard to know exactly what might have happened. But I can't reproduce the problem.
I don't have Word, so I can't test whether the problem might be with Word. But I'll attach both the WMF and EMF, and you could use them to import into Word, and find out if they look different in Word.
Edit
Just looking more closely at your file. I'm not sure if those 2 arrows are supposed to be on top of the book? But I didn't move them, in the files I attached. So part of those arrows are still behind the blue top of the book.
If you need to move them to the top too, you need to select them, then Object menu > Raise to Top (or this button on the control bar
)