Complex sentence: After Macbeth derives much of his motivation from the Witches perceived promise of invincibility--that no man born of woman can kill him--he interprets the prophecy to mean he is untainted by femininity, as if femininity were the source of vulnerability.
Split into simpler sentences: After Macbeth derives much of his motivation from the Witches perceived promise of invincibility: that no man born of woman can kill him. He interprets the prophecy to mean he is untainted by femininity, as if femininity were the source of vulnerability.