What is the ruling on a man marrying a woman with the intention of solving her crisis, with the dissolution of the marriage being conditional upon her repayment of her debt, while giving her the choice to either remain married or divorce thereafter?

If a woman marries and the amount you gave her is considered her mahr (dowry), she is not obliged to return it. Stipulating the return of the mahr, or not spending on her, or not consummating the marriage, are all void conditions that invalidate the condition itself but validate the contract. However, stipulating an option (choice) in the marriage contract, or limiting its duration, or making it contingent upon a condition, invalidates the marriage from its root. It is necessary to agree on an immediate or deferred mahr that is not refundable. You can lend her money with the condition that she repays it when she is able, but it is not permissible to stipulate that she shares in household expenses, as financial support is obligatory upon the husband. You are not obligated to borrow money to get her out of prison, but if you do, and you are unable to relieve her distress, then seek out someone among the wealthy who can help her.