In The Giver, the four qualities the Chief Elder says the Receiver of Memory must have are intelligence, integrity, courage, and wisdom. In addition, the Receiver of Memory must have the “Capacity to See Beyond." It is not clear what this capacity is exactly, but based on discussions with the current Receiver, the Chief Elder believes that Jonas has this.
Jonas himself questions his ability to fulfill the requirements the Receiver of Memory must have to be successful. At the Ceremony when Jonas is named to be an apprentice to the Receiver and learn how to be a Receiver himself, “for a moment he froze, consumed with despair.”
He believes that he does not have the required characteristics. He is intelligent, as evidenced by his performance as a top student in school. He has integrity. The Elder notes that Jonas has committed some minor transgressions as most people have, but when he has transgressed, he has always presented himself for chastisement promptly, which shows his integrity.
The position of Receiver requires courage, in part because the apprentice will experience a lot of pain during the training. Moreover, in addition to the physical pain, many of the memories the apprentice will experience will spark feelings that will be difficult.
The Elder explains to Jonas that he will have to deal “with pain of a magnitude that none of us here can comprehend because it is beyond our experience.” The Elder and the current Receiver both feel that Jonas is brave enough to endure the physical pain, even if he does not feel brave at the Ceremony.
The fourth essential attribute is wisdom, which is different from intelligence and comes with time. Jonas has not yet acquired wisdom, but the Elders and the Receiver are confident that he will acquire wisdom in time through his training.
The Capacity to See Beyond is more difficult to understand and probably refers to the ability to look beyond the superficial and understand deeper meanings.