Thoroughly maintain home with sibling I'm hesitant to leave (6)
I believe the answer is:
insist
'thoroughly maintain' is the definition.
'insist' can be an answer for 'maintain' (maintain can mean to insist something is true). I am unsure of the 'thoroughly' bit.
'home with sibling i'm hesitant to leave' is the wordplay.
I cannot really understand how this works, but
'home' could be 'in' ('he's home' can mean 'he's in') and 'in' is found in the answer.
'sibling' could be 'sis' (short for sister) and 'sis' is located in the answer.
A single letter 't' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for insist that I've seen before include "Assert firmly" , "express convinced viewpoint" , "Put one's foot down" , "Be firmly demanding" , "Beg persistently and urgently" .)