Somehow, not being alone is fixed (3-10)

I believe the answer is:

non-negotiable

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'fixed' is the definition.
Both the definition and answer are adjectives.
Perhaps there's a link between them I don't understand?

'somehow not being alone' is the wordplay.
'somehow' is an anagram indicator.
'not'+'being'+'alone'='notbeingalone'
'notbeingalone' anagrammed gives 'NON-NEGOTIABLE'.

'is' is the link.

Can you help me to learn more?

(Another definition for non-negotiable that I've seen is " Not open to discussion or modification".)

I've seen this clue in The Times.

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