Start to hope lancing boil and shine (7)
I believe the answer is:
shimmer
'shine' is the definition.
(shimmering is a kind of shining)
'start to hope lancing boil' is the wordplay.
'start to' indicates taking the first letters.
'lancing' is an insertion indicator (I've seen this in other clues).
'boil' becomes 'simmer' (simmering is a kind of boiling).
The initial letter of 'hope' is 'h'.
'h' inserted within 'simmer' is 'SHIMMER'.
'and' acts as a link.
(Other definitions for shimmer that I've seen before include "Twinkle" , "Give off tremulous light" , "Shine tremulously" , "glint"" , "Glisten (on water?)" .)