What the viewer of the movie or reader of this book is asked to believe is that something truly sublime has taken place, a masterpiece of love has been painted, and a noble thing worth more than life itself has just occurred. To answer those questions, I suggest you watch another film which, ironically, was playing in theatres at nearly the same time. But unlike the characters in Bridges of Madison County, she doesn't move quickly to resolve it. Nobody is in bed with each other within a couple of hours. She carries the tension for a long time, years, and then finally when it is resolved there is true sublimity.
Advent is about proper waiting.
It should therefore not to be confused with lent. The former symbolizes yearning and longing, the latter repentance. The spirituality of advent is not about repentance, but about carrying tension without prematurely resolving it so that what's born in us and in our world does not short-circuit the fullness that comes from respecting love's rhythms. It does it by helping to produce the heat required for generativity. An image might be helpful here.