If you install debtap from the AUR, then you can convert .deb packages into ALPM packages, as what Manjaro uses. 
pamac build debtap
HOWEVER…
The use of this tool and of these packages in Manjaro is not supported, and if it breaks your system, then you are on your own. Don’t come asking us for help with whatever problems would be caused by those packages, because you’ll receive the exact same answer every time, i.e.
Sorry, we don’t support that, and we told you so.
