あの日の誓い is a Weiß Schwarz card from 『テイルズ オブ』シリーズ TAL/S126-009. Compare listings from Singapore Weiß Schwarz sellers on CardJio, then jio them on WhatsApp.
【CONT】 If a CX with a Discovery Trigger is in your CX Area, this card in any area gains Discovery Trigger. 【AUTO】 When a CX with a Discovery Trigger is placed in your CX Area, choose 1 of your characters, this turn, it gets +500 power and the following ability, "【AUTO】 (1) When this attacks, you may pay cost. If you do, during the Trigger Step of this attack, perform Trigger Check twice."
This card was printed in Japanese only; the English text above is an unofficial community translation.