Becomes gradually more appealing to boy following girl on-line (5,2)

I believe the answer is:

grows on

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'becomes gradually more appealing' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'boy following girl on-line' is the wordplay.
'boy' becomes 'son' (synonyms).
'following' is a charade indicator (letters next to each other).
'girl on line' becomes 'grow' (I can't justify this - if you can you should believe this answer much more).
'son' after 'grow' is 'GROWS ON'.

'to' acts as a link.

Can you help me to learn more?

I've seen this clue in The Hindu.

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