How can the first wife make sure her husband is truly able to practise polygyny?

Ask for financial transparency and a written plan; if necessary, raise those concerns with the court. Discuss net income, debts, commitments to children and the estimated cost of a second household. A maintenance calculator can help make a realistic projection. During the application, the court assesses the husband's financial ability to support all his dependants, and the wife may give relevant evidence. Also make sure there is a plan for emergencies, such as losing his job. See the maintenance calculator, two-household finances and polygyny in Malaysia.