I came up with this sentence today:
Even she, who believed herself to be a revolutionary, could no more have broken her marital bangles than she could have driven a stake through her husband's heart.
I understand the meaning of this sentence. Here in this sentence two things are being compared. Both are negative sentences. The first sentence is no more than the second sentence. And ultimately giving out a meaning that both the sentences are not true.
But I wonder -

  1. The second part, that the first is being compared with - "she could have driven a stake through her husband's heart." - have no negative, yet how it means negative.
  2. How both the first part and second part tells out that both are impossible to her?