Ah i remember doing Harwood. Oh how i hated it XD
From the top of my head, this is what i can remember.
Triste means sad in some language, so the title means Sad, Sad.
It can be interpreted in many ways. Commone interpretations are: the poem is about the inextricable connection between soul/spirit and heart/body, the time between lovemaking and sleep, the soul trying to escape from the body etc etc
There are plenty of techniques including repetition, references to christianity and symoblism.