In a communication class in college, I learned only 7% of of communication is the words chosen. That makes communicating with the right amount of confidence extremely important. For engineers, trained to rely on calculations for proof rather than intuition, it doesn’t come natural. However, if the research was thorough, the calculations are done, and testing will be done appropriately, report to the client or executives while being relaxed, smiling, and looking them in the eye.
You know what you’re doing. You’ve got this.