Hey Wanda,
Nice to know this piece spoke to you. I do my best to write based on what I experienced instead of pure theroy.
By the sentence you refer, I meant that it's a journey to become a solid Scrum Master and not a Sprint. It's a complex role and it entails a lot of responsibilities and requires significant expertise. My belief is that one must have seen a lot in the business world before becoming a Scrum Master. That's what I meant by takes a lot of skin. Yet, a successful Scrum Master is humble by meeting the team where they are and asking questions that help them move further, instead of giving answers.