I think one of the things that keeps you from needing to explain is knowing how to give orders. If you speak to people without yelling, firmly, in a deep voice, and tell them to do something as if you expect they will just rush off and do it, often they will.

I think experience in giving orders helps. It's something I had to learn how to do. Exercise authority with the idea and expectation that people will just follow it.

I think one thing to be one guard for is reliance on someone before they show reliability. If she is not willing to follow orders, then relying on her to do so is not a good idea.

Some discomfort may encourage her to come around.

The real risk is keeping you and her alive, until she does come around. Sometimes, you may be to just force her, sometimes, you may need to cut her loose.

If you have to explain, short, to the point. Same like giving an order.