South holds, and hears
1♥ = 5+ hearts
3♦ = limit raise+ with exactly 3 hearts
Pass over the double = game try or better (3♥ is the weakest call)
Pass over 5♦ = forcing
before South has a chance to lead, West says "I wish you hadn't bid partner, I was waiting to double this"
South thinks for a long time before leading, and eventually leads the jack of spades. Dummy has
♠Ax
♥Q86x
♦A10952
♣52
The contract makes. It would be one off on a heart (or club) lead (Declarer has KQx of spades.). FWIW, although irrelevant, 4Hx would make.
South says that he would have led a heart, but the comment make him think that dummy had something like AQx or AJxx opposite a singleton or void, and that put him off a heart lead.