At this point it's unclear what could possibly convince Cersei to enter into another political marriage — especially if Euron's fleet of 1,000 ships wasn't enough to sway her. However, that hasn't stopped fans from theorizing about how he intends to gain her trust.
Some think the gift will be none other than Cersei and Jaime's , who became Daenerys' Hand of the Queen after fleeing King's Landing in season four. Euron referenced Tyrion twice during his pitch, alluding first to Twyin's death at Tyrion's hands and then defending his murder of Balon by suggesting that Cersei see how "wonderful" it feels to kill her own brother.
But the gift could also be an actual object. In George R.R. Martin's A Song of Ice and Fire book series, Euron claims to be in possession of the Dragonbinder — a sorcerous horn that is used to control dragons.
"That horn you heard I found amongst the smoking ruins that were Valyria, where no man has dared to walk but me," Euron says in A Feast for Crows. "You heard its call, and felt its power. It is a dragon horn, bound with bands of red gold and Valyrian steel graven with enchantments. The dragonlords of old sounded such horns, before the Doom devoured them. With this horn, ironmen, I can bind dragons to my will."
With Daenerys intent on taking the Iron Throne from Cersei, it seems like a gift that could nullify the threat of Dany's three dragons would be the most useful of them all.
"Stormborn," the second episode of Game of Thrones' seventh season airs July 23 at 9 p.m. on HBO.
Source : http://time.com/4861495/game-of-thrones-euron-greyjoy-gift-cersei-lannister/