Python understands forward-slashes on both Windows and Linux.
Also double forward-slashes at the beginning can mean a server name.
So //home/james could be trying to find a server called home with a share called james on it.
So to test:
I downloaded a sample MP3 from here.
Installed playsound using pip3
pip3 install playsound
Added the following code to tst.py
from playsound import playsound
playsound('/home/james/Downloads/sample-3s.mp3')
Ran my code
python3 tst.py
And it played the sample MP3 successfully.
Can you trying listening to the MP3 by double-clicking on it and seeing if it plays?
Check that the file is actually in /home/zsarthak/Music, noting that Linux is case-sensitive and so Music and music are two different folders.
Run the following from the command line (terminal).
ls -l /home/zsarthak/Music
Do you see your file or do you get an error like
ls: cannot access '/home/zsarthak/Music': No such file or directory