If you do not know this character well, allow me to explain what Starshine is.  For the most part, she looks elvan, but she is not.  She is part of a rare and mystical race that Lorata knows as the Starr.  They are angelic beings with powerful magic and a gift for song and music.  The are very peaceful, though now and then they will fight to protect whom and what they love.  I have also, in the books, described that as aetherian and celestial.  The people of Lorata consider them in part a mystery.

Starshine grew up in a kingdom known for its love of bards.  I cannot say much about her heritage without causing terrible spoilers, so bear with me.  What I can say is that she loves music, plays several instruments, and sings, well… like an angel.  And, as you have read, she has a close relationship with Zarrek.  She also speaks the language of the Starr, and within it knows a great deal of poetry.  She knows a great deal of poetry in other languages as well (mostly the common tongue), but the Starr poetry is meant to be especially profound.

In Traipsing Light and Shadows, she had this to say about her relationship with Zarrek, which many consider to be strange:

In the brightness of day

there shines but one bright star.

Only in the nighttime blanket

of the æther so black

can the innumerable stars of all the distant universe

twinkle and light the way.