From the start, he was crazy about the little darling (10)
I believe the answer is:
sweetheart
'darling' is the definition.
(I've seen this before)
'from the start he was crazy about the little' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'the' is 'eth' which is located in the answer.
'he' could be 'art' and 'art' is found within the answer.
'little' could be 'wee' (similar in meaning) and 'wee' is found in the answer.
A single letter 's' remains which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sweetheart that I've seen before include "Term of endearment" , "Dear" , "ducks" , "flame?" , "Love" .)