The Wedding Girl; by Madeleine Wickham (Sophie Kinsella).

Sophie Kinsella (here using another nom de plume) has developed into or proved to be more than frivolous entertainment for young women and teenage girls, in fact even with her shopaholic series that was true - generally she takes up problems the girls or young women are likely to encounter whether in themselves or in the world and find little if any help from elsewhere, and then proceeds to deal with it all in a sympathetic way with a charming tale woven to a happy ending. This one takes up a slightly deeper level of a problem than shopaholic tendency and makes one go through various pitfalls a young woman can fall into in the happiest of circumstances with no real villains (unless a middle aged woman relative counts as one - but that is overcome easily enough!) - in the process of a social diatribe, though, she does give a rather good picture of what seemingly pretty people are like, in the descriptions of St Catherine flock in general and Tom and Francesca in particular.