Money or Love by Barbara Cartland

Sir Robin Dunstead returns from India after his father's death to find that he has inherited two of the largest ancestral houses in England, but no money to restore them. Amazed to find both houses empty of servants and in a state of disrepair he berates himself for not returning home earlier.
Stunned to learn that his father has sold everything of value that is not entailed to future generations and squandered the family fortune on selfish pursuits, Robin is left with no income and not even enough money to buy food for himself and his lovely sister, Alena.
In complete despair Robin commissions a forger to copy two lesser-known priceless paintings that are entailed for future generations and raise enough money to launch Alena and himself in society in the hope of attracting rich American's dazzled by her beauty and his title. Robin is adamant; they must both marry for money to save the family estate, forgetting any dreams of true love.
Their plan seems set to work, until Alena meets a charming artist, Vincent, who shares her appreciation of art but has no fortune. Can she really quash the blossoming feelings she has for Vincent in order to marry a millionaire?
Meanwhile, Robin has his own dilemma as he chases a hugely wealthy heiress. Uncomfortable with his new role as a penniless fortune hunter, Robin finds it much harder to compromise his personal values than he ever imagined.
As brother and sister struggle with the realities of their decision both are forced to reconsider their choices – personal happiness and poverty, or the financial security that only a wealthy spouse can offer.