Amulet of Assertiveness (Yellow)

Go again

Attack Reaction - Destroy this: Target attack gets "When this hits, banish the top card of your deck. If it's an attack action card, you may play it this turn." Activate this only if you have 4 or more cards in hand.

Rulings

From the Everfest release notes

Amulet of Assertiveness’ activated ability is an attack reaction. You may activate it during the reaction window when you are the attacking hero.
An attack is considered to have hit if it deals damage during the damage step of combat.
You cannot defend with Amulet of Assertiveness as it has no defense property. (This is different than if it had a defense value of 0.)
If the banished card is not played during the turn it is still banished and will remain banished indefinitely.
The ability will still resolve even if you have less than 4 cards in your hand on resolution of the activated layer.

Keyword notes

Go again - Go again allows multiple actions to be played in a turn when usually playing an action with use up your action point, and therefore end your turn. A card with go again gives the controller of that card or activated ability 1 action point when it resolves.

When an action with go again resolves, its controller gains 1 action point.
Multiple instances of go again on the same card or activated ability do not stack. If a card or activated ability has multiple instances of go again when it resolves its controller gains 1 action point only.
If an action with go again does not resolve, its controller does not gain 1 action point.
You cannot reveal a card with no to Belittle. The card must have a value to its power that is 3 or less. (0 is a value)