With annona seeds the best guarantee is to get them really fresh. Older seeds bigger gamble.
This is true.Ive ordered Cherimoya seeds from different sellers from Ebay ,6 times ,until i got one seed sprouting.
Same happened with sugar apples and a few otthers annonaceae like Uvaria grandiflora,etc.
Seed pirates thogh are serious sellers from wich i got all my seeds allready germinated by them ( in plastic bags with stirofoam ). I havent ordered annonaceae from them thogh.
Lately i quit completely to buy any annonaceae seeds and prefer to buy live plants.