beta
Her family used all their money for her extravagance and luxuries and brought a crisis of bankruptcy...
FL gets reincarnated as some character with family debts. She comes across a missing person leaflet: a duke is looking for a lost child and offers a hefty reward. She uses her knowledge from the novel and brings him the child. The child gets attached to the FL and doesn’t want to leave so the duke offers her a contract marriage.
tsundere ML