Crossword Genius

Letter bound to have shown sympathy (6)

Ross
I'm a little stuck... Click here to teach me more about this clue!

'shown sympathy' is the definition.
Although both the answer and definition are past participle verbs, I don't see how they can define each other.

'letter bound to have' is the wordplay.
'letter' becomes 'and' (I can't justify this - if you can you should believe this answer much more).
'bound' is an insertion indicator.
'to have' becomes 'bed' (synonyms).
'and' going within 'bed' is 'BANDED'.

Can you help me to learn more?

I've seen this clue in The Globe and Mail.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.