Inkscape will be officially supported on Mac with the release of version 1.0, which is currently under development.
Alpha releases of Inkscape 1.0 are available that more or less "just work" on Mac. Bugs should be expected because alpha releases are even less stable than beta releases.
Installing Inkscape 1.0alpha2 on Mac
Inkscape 1.0alpha2 is the first release to offer a download for Mac that works as a native application.
You can download the dmg from https://inkscape.org/release/inkscape-1.0alpha2/mac-os-x/dl/
Once you have opened the dmg, drag "Inkscape" to "Applications".
Launching Inkscape for the first time
Depending on your security settings, you may see an error like the following when you double-click "Inkscape" to launch it:
"Inkscape" is an app downloaded from the Internet. Are you sure you want to open it?
Click "Open" and Inkscape should open.