One with a nest-egg doesn't start to declare (4)
I believe the answer is:
aver
'declare' is the definition.
(averring is a kind of declaring)
'one with a nest-egg doesn't start' is the wordplay.
I cannot really understand how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is located in the answer.
The remaining letters 'ver' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'to' is the link.
Can you help me to learn more?
(Other definitions for aver that I've seen before include "being assertive" , "Maintain - assert - allege" , "claim" , "Prove to be true" , "State firmly, perhaps rave" .)