The smart one and the pretty one - Claire Scovell LaZebnik

When Ava Nickerson was a child, her mother jokingly betrothed her to a friend's son, and the contract the parents made has stayed safely buried for years. Now that still-single Ava is closing in on thirty, no one even remembers she was once "engaged" to the Markowitz boy.
But when their mother is diagnosed with cancer, Ava's prodigal little sister Lauren comes home to Los Angeles where she stumbles across the decades-old document.
Frustrated and embarrassed by Ava's constant lectures about financial responsibility (all because she's in a little debt. Okay, a lot of debt), Lauren decides to do some sisterly interfering of her own and tracks down her sister's childhood fianc. When she finds him, the highly inappropriate, twice-divorced, but incredibly charming Russell Markowitz is all too happy to re-enter the Nickerson sisters' lives, and always-accountable Ava is forced to consider just how binding a contract really is . . .