This study captured the perspectives of 887 working adults to explore views of professionalism, authenticity, and effectiveness of AI-generated messages. With a 3 (message type) × 2 (disclosed vs. undisclosed) × 2 (ChatGPT-generated vs. Google-generated AI messages) design, professionals generally view AI-generated content favorably in all conditions. Across all messages, professionals consistently rated the AI-generated messages as professional, effective, efficient, confident, and direct. They rate sincerity and caring slightly lower in some disclosed conditions, particularly for ChatGPT-generated messages, suggesting the importance of tool selection when using generative AI for workplace writing. Those professionals who use AI more frequently for work are more likely to view AI-assisted writing as authentic, effective, and confidence-building. Implications for teaching business communication, including the need to address AI literacy, and suggestions for future research are provided.