Wolf the gezeirah of David was yichud penuya. Yichud isha is d’oraysa.
Fair enough, but my understanding of a live-in maid is that they are usually single, no? If married, wouldn’t they live with their spouse?
Essentially any Derabbanan is a Deoraysoh of Lo Sasur.
While that is technically true, it is not applied for practical reasons. If you actually applied that reasoning, then there would never be *anything* that is d’rabbanan. You could never apply the rule of “safek rabbannan l’hakel” since every d’rabbannan is also d’oreisa.
The Wolf