People, while trusting by nature, are very perceptive and can find any hint of insincerity or lack of credibility. Listen first for understanding. Writing and speaking, as arts, improve with study and practice. Get help with tough communications. They can provide a clarifying perspective for you.
Simplicity is better.
Don't hide behind language. Complex, wordy communications may leave understanding behind in an alphabetical dust. Choose clarification over obfuscation.