Far be it from me to say categorically, "No, this never happened." In the 21st century US, slavery is illegal and widely acknowledged as horrific, and dowry/reverse dowry are not standard cultural practices. Yet I'm aware of the realities of human trafficking and also of subcultures who practice what appears from the outside to be the exchange of money for prospective spouses. But just like selling one's kids would not be called a "modern American practice," it just doesn't make sense in the Middle Ages.

There is first of all the question of "woman as property." There are two basic ways medievalists (and early modernists) have approached this through law: coverture and rape. Coverture is the idea that a woman is not a legal adult in her own right--she is "covered" by her closest male relative; generally her husband or father. She cannot make contracts or represent herself in court (sue those who wrong her in business); she needs a legal guardian. Essentially, she is a child. But that's not the same thing as a slave who can be bought or sold.

Second, rape laws. The Middle Ages is actually a transitional time between rape being seen as a crime against the husband/father of the woman, for spoiling his "property", and as a crime against the woman herself. This shift ends up not being the awesome leap for women's rights that you might think. However, from a canon law perspective, by the late Middle Ages rape was a crime against the woman. (Now, how it was treated on a case by case basis in individual communities is another question.)

Second, there is the matter of dowry. In the late Middle Ages, dowry was fairly standard practice across western Europe. For middle and lower classes, though, it was sometimes as much a question of what each could bring to a potential marriage as far as supporting themselves rather than a one-way payment. However, the pressure was definitely on women to bring more money to the table. Northwest Europe, including England, gives rise from 1300 onwards to what is known as the "European Marriage Pattern" (the EMP that gave you the money to have an Internet connection, not the EMP that could ruin it). This is characterized by a fairly late age at first marriage for women and men, generally in their early 20s. Both women and men spent time working, the women often as domestic servants, to earn money to set themselves up for marriage. Indeed, medieval partnerships were economic and utilitarian, not just love-based, even beyond the "noble parents betrothing their toddlers" stereotype. Especially when a wife was expected to labor alongside her husband in his (legally) workshop or on his farm, matching money and skills was crucial. Notably, the wages earned by adolescent girls working was theirs to take to marriage, even through coverture. (Women could absolutely own property, inherit it, etc.; they just couldn't dispose of it--make legal contracts--without male permission).

With the above two points in mind, we can say that women had it pretty bad in the Middle Ages, but they were not slaves, not property to be bought and sold. When a partnership was being formed, the money that a woman could bring to the marriage was pretty darn important, in fact, it was so important that she would usually spend a decade working first in order to get enough of it to find a partner at all.

Of course, so far I've been discussing marriage, and it's pretty clear that what is happening in World Without End is not marriage. To which there are a couple things to point out. First, in the domestic servitude I discussed above, sexual exploitation was rampant. Once we start having court records, into the early modern era, young women frequently level complaints in court against their employers. We see a similar pattern emerge on the continent, where Christian and Jewish teenage girls might work in cross-confessional homes. Both Jewish and Christian authorities try to ban these employment arrangements because of how often they lead to miscegenation. But again--the person being paid in these cases (well, ideally, and that is what some of the court cases are about) is the woman, not her father.

Second, Ruth Mazo Karras has scraped together various sources to suggest a picture of rural prostitution in late medieval England, as opposed to the legal brothels infamous in Southwark and the illegal streetwalkers. What she finds is an endemic situation of "occasional prostitution"--that is, supply and demand balancing out on an ad hoc basis, exchanging some coins but also goods and gifts for sex. The buyers in Follett's scene, if Karras is correct, would not have to resort to such extremes to obtain cheap disposable sex outside marriage if that's what they wanted. (There is of course also the matter of straightforward raptus in both the rape and abduction senses.)

Basically, this whole scene does not make sense in the late Middle Ages. It's a fiction book, and you can always say, "Well, this is that one special case." I have talked in very broad strokes in this post for a reason: the question asks about a work of historical fiction. For me, finding an HF book 'realistic' requires capturing the overall texture of a time period, rather than every single individual case. That makes normative sources, like law codes, a surprisingly good source for this kind of investigation, although there still has to be attention to whether the laws derived from real practice or paranoia (no, there were no Heretics of the Free Spirit engaging in mass orgies and pouring Eucharist wine all over each other in desecration of the sacrament).

So if Follett was going for realistic historical fiction (which Caris' entire plotline tells me he clearly was not; witchcraft in the early modern sense was Not A Thing in the fourteenth century and convent leadership and departure does not work that way), a scene like this goes a long way to spoil the illusion for me.