In Chaucer's The Canterbury Tales, the tale the Wife of Bath tells correlates not only with her personality, but also with the reason for which she is on the pilgrimage.
The Wife of Bath is a woman of generous girth: she is difficult to miss as she travels, well dressed in a lovely fabric, red stockings, etc. She is deaf, loud, laughing, bawdy and hard to miss, but she is likable. She is a woman of wealth. She is generous to the Church. However, while the usual purpose of the pilgrimage is to allow people to travel to a holy place and give God thanks for all that He has done, the Wife of Bath is more interested in finding another husband. She has buried several already (meaning she has outlived them). While married several times, she has also (we can infer) enjoyed the company of men her entire life:
With five churched husbands bringing joy and strife,
Not counting other company in youth... (460-461)
She is a good-humored woman: if she is insulted, she can laugh it off; she is also a willing lover, well versed in "the dance" (love-making):
In company well could she laugh her slurs.
The remedies of love she knew, perchance,
For of that art she'd learned the old, old dance. (475-477)
By these descriptions in The Prologue to the Canterbury Tales, the reader can infer that the Wife of Bath is open and honest. Unlike most of the servants of the Church who accompany her on this pilgrimage (who are corrupt and hypocritical), the Wife of Bath is honest about her motives.
The story she tells when the group stops for the day supports the idea of marriage, sex and fidelity, but Chaucer also uses it to tell what he sees as a deeper truth—what a woman really wants. As it begins, we learn:
And so it happened that this King Arthur had in his court a lusty young knight, who one day came riding from the river; and it happened that he saw walking ahead of him a maiden, whom he ravished, in spite of all her resistance.
Knights were expected to be chivalrous, defending a lady's honor, not committing rape. So when his offense was discovered, Arthur delivered his sentence: death. However, the Queen and the women begged the King for mercy. So Arthur (presented as a wise man by the Wife of Bath—who gives in to his wife's entreaties) allows that the Queen may decide if the knight live or die.
The Queen presents a riddle to the knight—he has a year to find what it is that a woman truly wants from a man. She sends him on his way to find the answer. Returning the last day without any idea, the knight is ready to face death until he is approached by an old, unattractive woman—a crone...
...no one could imagine a fouler creature. (999)
She offers to tell him the answer to the riddle, but only if he will grant her one request. He gives his word and they go before the Queen and all the women at court. He tells them that what women want is their way in all things with their husbands. The answer is acceptable, but then the crone appeals to the Queen that the knight should honor his promise to her: she wants to marry him and have him love her.
The knight wants none of it, but honors his word. He is less than noble on their wedding night, explaining why he is so unsettled.
You are so loathly and so old, and come of so low a lineage as well, that it is small wonder that I toss and turn. I wish to God my heart would burst! (1103)
The old woman rationalizes that each of these things (age, ugliness, poverty) is insignificant. Then she gives the knight a choice: she can be beautiful and unfaithful, or she can be old and ugly and faithful to him, all of his days. Wisely (as had Arthur with the Queen earlier), the knight allows that she should decide for him. In giving her "sovereignty" over him, she grants him all that he wants. An enchantress, she becomes young and beautiful, and they live happily till the end of their days.
The Wife of Bath is straightforward (as is her tale).
She is well versed in marriage and lovemaking. Her theory is that the woman must dominate in marriage. To make her point, she tells a tale of a loathsome lady who, when her husband is obedient, becomes fair.
For those who might find her unattractive, her point is that she would make sure they were pleased in marriage. We can infer that this lusty woman must know how to please a man, not only with her long history in the company of men, but with her five marriages as well. Her tale is meant (in the words of the crone) to discredit the things about her that a man might find unappealing (physical characteristics). However, she promises that if a man will give her her way in all things, she will make certain that he is happy.
I don't see the Wife of Bath as a hypocrite at all. Rather, she is a woman who does not try to be something she is not. Her tale is used to enlighten the men present that looks aren't everything; there are other things more important. As to going on the pilgrimage for a purpose other than visiting a holy shrine, her generosity to the Church shows that she is faithful.