I interpret “put the very best face on” as a variation of “put a good/brave/bold face on something”=act as if something unpleasant or upsetting is not as bad as it really is. talk something up=to speak with enthusiasm about something. A “facade” is literally “the face of a building”, but it can also mean “a deceptive outward appearance”: ‘her flawless public facade masked private despair’ Saying that her “facade cracks” means that it becomes evident that she is hiding her true feelings. The facade breaks apart and you can see what’s behind it.

The author is saying the person in the story wanted to make the best of her situation. Meaning, even though she had bad things happen in her past, she wants to move on with her life and focus on what is in the future instead. Does this help?