The subtitle of Tess of the d'Urbervilles is A Pure Woman. It may be supposed from this that Hardy's objective is to redefine "pure woman" and contradict the standards of Victorian society that had developed a progressively restrictive definition of and role for woman while male philosophers and theologians discussed "the Woman question" and relegated women more and more to hearth and home under the label of "the Angel in the house."
It may thus be concluded that Hardy does present Tess as a pure woman but that critics and readers of his time had very strong opinions that diverged radically from his own, which may be wondered at since Dickens and the Brontës were from earlier dates also chipping away at the narrowing constraints directing womanhood in continually confining paths.
[Mrs. Clare]: "And that she is pure and virtuous goes without question?"
[Angel Clare]: "Pure and virtuous, of course, she is."
The way that Hardy presents Tess as pure is to develop the techniques of the newly sprung Realist school of literature and develop the psychological aspects of important characters. This means that Hardy exposes the motives, thoughts, beliefs, in inner emotional and logical struggles of the characters. In this way, the reader sees plainly who is admirable and who is not and for what reasons.
In this way, we know that Angel Clare is at his essence good but confused by contradictory impulses as he "observed his own inconsistencies in dwelling upon accidents in Tess's life." We know that Alec Stokes-d'Urberville is at his essence villainous as he laughs off and manipulates Tess' pure impulses and sentiments. We know that Tess is indeed pure, regardless of the accidents, coincidences and bad luck of fate [Hardy's philosophy of causation in life] because we know her inner convictions, thoughts, and motives that inspire her external attempts at actions in events that exert pressure upon her.
Thus we can judge outcomes rightly and can value character correctly. The end result is that it is clear that Hardy does present Tess as pure, a representation his society rebelled against, and it is clear that Hardy wishes us to see Tess as pure.
Thus Tess walks on; a figure which is part of the landscape; a fieldwoman pure and simple, in winter guise;...