I love it, and far prefer it to
Tristan for a girl. However, I would only spell it Tristina, as Trystina fairly obviously contains "tryst", a vocabulary word I wouldn't care for my child's to remind me of.
Miranda
"Multiple exclamation marks are a sure sign of diseased mind" -- Terry Pratchett
!!!!!!!!!! ← Maud, John, Alice, Peter, Emma, Edith, Lewis, Henry, Isabel, and Joseph