When selecting a secure payment gateway for your email marketing campaigns, consider the following factors: - Security Features: Ensure the gateway offers encryption, tokenization, and fraud detection. - Integration: Check if the gateway can easily integrate with your existing email marketing platform. - User Experience: Make sure the payment process is straightforward and user-friendly. - Fees: Compare transaction fees and other costs associated with the gateway. - Support: Opt for a provider that offers robust customer support to handle any issues that may arise.