Final answer:
User acceptance testing would best support the project manager's objective of validating the developer's interpretation and understanding of the user's request.
Step-by-step explanation:
The project manager can best support the objective of validating the developer's interpretation and understanding of the user's request through User acceptance testing. User acceptance testing is a process where the software is tested by end-users under real-life scenarios to ensure it meets the requirements and is ready for deployment. This testing phase allows users to provide feedback, identify any issues, and validate that the software aligns with the user's expectations.