Pass card to successor, swearing? (4,2,5)
I believe the answer is:
hand on heart
'pass' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'card to successor swearing?' is the wordplay.
'card' becomes 'heart' (the hearts are a playing card suit).
'to' means one lot of letters go next to another (I've seen this in other clues).
'successor swearing?' becomes 'handon' (I can't justify this - if you can you should give a lot more credence to this answer).
'heart' after 'handon' is 'HAND ON HEART'.
Can you help me to learn more?
(Another definition for hand on heart that I've seen is " honestly".)