One may be in doubt as to how to make a better offer (6)
I believe the answer is:
outbid
'offer' is the definition.
(I know that outbid is a type of offer)
'one may be in doubt as to how to make a better' is the wordplay.
I cannot really see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
an anagram of 'doubt' is 'outbd' which is located in the left over letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for outbid that I've seen before include "Offer more for something than (another person)" , "Go higher than another at an auction" , "But I do (anag)" , "Offer more then competitors at auction" , "Make a higher offer than another" .)