Succinct way to express that a person does well with emotions

emotional maturity

emotionally mature aka emotional intelligent.

emotional maturity is the buzz word for this.

Phd's writing about this topic: subtitle: a path to emotional maturity

Emotional intelligence (EI), also known as Emotional quotient (EQ) and Emotional Intelligence Quotient(EIQ), is the capability of individuals to recognize their own emotions and those of others, discern between different feelings and label them appropriately, use emotional information to guide thinking and behavior, and manage and/or adjust emotions to adapt to environments or achieve one's goal(s). - wikipedia

I would describe Susan as an empath. She seems to always know what you need to hear, whether it is good or bad. Please read the following definitions for reference:

(chiefly in science fiction) a person with the paranormal ability to perceive the mental or emotional state of another individual. [—The Oxford Dictionary of English, Third Edition (©2010)]

One who is highly sensitive to the feelings of others and has a high capacity for empathy: "He was also something of an empath, intuitively alert, it would seem, to what was going on behind those faces" (Roberta Smith). [—The American Heritage Dictionary, 5th edition (©2018)]