Slow Witheringand paying superior action card

Slow Withering

Gehenna.
Requires at least 1 other Gehenna event in play.
Do not replace until a vampire commits diablerie.

Cards requiring any superior Disciplines cost 1 additional blood.
Any vampire who commits diablerie is immune to this effect until a Gehenna event is played.

If someone play action card superior,him need to pay when play card,or only if action sucesful?

Since it is increasing the cost of the card, and an action card's cost is paid when the action is successful, I'd say it follows the regular method for action cards.

Note that the action's cost, if any, is only paid if the action succeeds; the cost is not paid if the action is blocked.