Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
The Wife of Bath really, really loves life and all its pleasures, and her enthusiasm comes out in what we're calling the exuberant tone of her Prologue. For example, when the Wife imagines Solomon's wedding nights, she can barely contain her excitement at the thought, and can't help but identify with him, saying "As, wolde God, it leveful wer for me / To be refresshed half so oft as he! / Which yifte of God hadde he, for all his wyvis!" (37-39). She has the same sort of reaction when she recalls the lusty days of her youth, which recollections she says tickle her "herte roote" (477). You get the feeling from all this that the Wife is sincerely taking pleasure in recalling the sexual exploits of herself and others, and even if you don't agree with her morals, you can't help but be won over by her enthusiasm.
Going hand-in-hand with all this exuberance is an emphatic tone that brooks no opposition. The Wife does not speak in terms of shades of grey; she is extremely definite and assured in her statements. She peppers her narrative with emphases like "Lord Christ!" and "God woot," in effect taking God as her witness to the truth of her statements. The emphatic tone of the Prologue is enhanced by the extremity of the Wife's lifestyle. She's not just a wife, but five times a wife, and "welcome the sixte, whan that evere he shal" (51). The Wife's refusal to do things by halves and her gusto in defending her lifestyle create the highly emphatic tone of her Prologue.