1.
sudo dpkg --add-architecture i386
2.
wget -nc https://dl.winehq.org/wine-builds/Release.key
3.
sudo apt-key add Release.key
4.
sudo apt-add-repository 'deb https://dl.winehq.org/wine-builds/debian/ stretch main'
5.
sudo apt-get update
6. If you want to get the stable version:
sudo apt-get install --install-recommends winehq-stable
It worked for me like a charm. I hope it works for you if you need to run any Windows programs in LMDE3. The same procedure works for Mint 19 by changing #4 above to 'deb https://dl.winehq.org/wine-builds/ubuntu/ bionic main'
Instructions adapted from https://wiki.winehq.org/Debian.