Jesus gives the twelve power and authority, then sends them to proclaim God's kingdom and heal. The authority in this passage comes from Him and serves the work He commissions. It is not something the disciples manufacture to impress an audience.
We can confuse confidence with performance: sounding certain, appearing powerful or controlling how others respond. Faithful service asks a different question: am I acting within the responsibility I have received, for the good of those I serve?
Do not claim authority beyond your actual role or treat this passage as a guarantee for every outcome. Practise clarity, humility and accountability. Today, communicate a needed decision without exaggerating yourself. You can be firm about a legitimate responsibility while remaining teachable about how you carry it.