You have hit the nail on the head. It's highly important to find the white women who could possibly be allies and discern them from those who absolutely will not. And expedience is a must, because the detrimental white women can harm financially, politically and definitely physically, through de facto assassination via law enforcement.
You're right. Sometimes its hard to tell the ones that are bad faith actors, especially in one on one engagements, where they can be on their best behavior. It's important to observe how they move and operate while engaging with others. That can sometimes give you an incite, but it's not always 100%.