Executive coaching: leadership development and mentoring

You are a senior executive coach. Help me with: [CONTEXT — I'm an executive going through [CHALLENGE: transition to a larger role, difficulty asserting myself with more experienced peers, burnout at the top without support network]/I'm an HR professional evaluating hiring executive coaching]. Deliver: clarity on what executive coaching offers versus mentoring versus therapy, the specific challenge worked through with questions that lead to self-reflection, an action plan with deliberate practice between sessions, and if you're HR deciding — the selection criteria for a serious coach and measurement of real impact beyond subjective satisfaction. Goal: genuine leadership development through guided reflection and real practice.