seize; grasp; hold. It's rarely used in its literal sense but the metaphorical sense is just that.
他对成功很有把握。Success is within his seize.
To have 把握 in something you need both confidence and ability, although when people say
有把握/没有把握/失去把握 they are actually emphasizing on the confidence side, e.g.
我有把握拿满分。I have confidence in getting full marks in the exam.
失去把握 can also mean
lose control, though not necessary 'lose control over oneself'.
In your first sentence, "她的把握全失去了", there are two possible interpretations.
- She lost her 'seize' (confidence or leverage) in the affair.
- She lost her 'seize' (control) over herself.
From the limited context in your question I am unable to tell which one is it. In addition to the plot, it also has a lot to do with the author's language style.
Similarly, the second sentence has two possible meanings "她现在是个自主、有把握的女人。"
- She has become a woman of determination and confidence (she has general confidence in her own actions and decisions).
- She has become a woman of determination and means (she has a lot of levers/maneuvers in the things she does).
That again depends on more context to nail down.