It is as if Browning disdained for the time all the philosophy of heredity and environment; and indeed it was characteristic of him to believe in the sudden creation of beauty, purity and nobility out of their contraries and in spite of them.

The miracle of the unrelated birth of genius--that out of the dunghill might spring the lily, and out of the stratum of crime the saint--was an article of faith with him.

Nature's or God's surprises were dear to him; and nothing purer, tenderer, sweeter, more natural, womanly and saintly was ever made than Pompilia, the daughter of a vagrant impurity, the child of crime, the girl who grew to womanhood in mean and vulgar circumstances.
The only hatred she earns is the hatred of Count Guido her husband, the devil who has tortured and murdered her--the hatred of evil for good.
When Count Guido, condemned to death, bursts into the unrestrained expression of his own nature, he cannot say one word about Pompilia which is not set on fire by a hell of hatred.

Nothing in Browning's writing is more vivid, more intense, than these sudden outbursts of tiger fierceness against his wife.

They lift and enhance the image of Pompilia.
When she comes into contact with other characters such as the Archbishop and the Governor, men overlaid with long-deposited crusts of convention, she wins a vague pity from them, but her simplicity, naturalness and saintliness are nearly as repugnant to social convention as her goodness is to villany; and Browning has, all through the poem, individualised in Pompilia the natural simplicity of goodness in opposition to the artificial moralities of conservative society.