If you don't have much Psyche, purchase some from the Wretched Broker or keep exploring the Underworld and the surface until you have enough to increase your Grasp. Each time you increase your Grasp, it will cost more to increase it the next time. The amount of Psyche needed to increase your Grasp adds up very quickly, so keep collecting it on your runs or at the Wretched Broker so you can equip more Arcana Cards to help you out in battle.