What does "turn out" mean here?

What type of person is not containable? Is it a common expression?

If someone is "not containable" it means that they are not able to be contained or held down. In this case, this means that she is unable to be controlled by anyone else. This is not a very common expression to use when talking about people, but it can be used to refer to someone's emotions or feelings. Ex: Her excitement about the promotion was uncontainable. Ex: I am unable to contain my stress.

What does it mean by "break you as a leader?"

To "make or break it" basically means to succeed or fail at something, so "make or break you as a leader here" means "to succeed or fail as a leader". Ex: Height won't make or break you as an athlete, but it can definitely be helpful. Ex: For children, having a healthy family environment can make or break you when they become adults.

What's "break off" mean here?

Here, "break off" means to remove something from a whole or larger unit. Ex: I broke off a few pieces of chocolate from the chocolate bar for Susan. Ex: We'll break off the end part of the pole so that it fits into the hole.

Can you tell me some alternative words that can replace "devoting"?

To "devote" refers to giving up one's time or resources for something. Synonyms for "devoting" in this case are "giving", "dedicating", "sacrificing", and "committing". Any of these words can be replaced with "devoting" in this sentence and used as an alternative for the same meaning.

What's "Mayfair" mean?

"Mayfair" is an area of London and is known to be more affluent. It's very close to Buckingham palace. But it's the set location for Bridgeton, at least on camera, not in real life, but they set it up to look like actual Mayfair. Ex: We're going to Mayfair for the day. Care to join us? Ex: I was at Mayfair last week for a meeting.