At the end of the day, he first promised Arsenal that he loved the club and loved playing for them, now with the same tongue he is promising he would now play for united, if the media reports are true.

He could always train with united and then return to Arsenal to sign his first contract at 17. Because nothing is concrete until he is 17, so united have nothing more than a word of mouth promise if anything. Maybe the same word of mouth he gave Arsenal.

Plus he will be taking a huge risk if his goals dry up in the united academy and they then change their mind about his worth.
He should have stuck with the very creative Arsenal academy team that has been assisting his goals through their creativity.
I am not sure that the united academy team would know his style and runs and lay on the same good assists he is use to at Arsenal.
It maybe his parents that has turned his head or an agent trying to make a quick buck off of him, but he is foolish to leave a club that has nurturedcthe likes of Saka because Arteta must hold him in the same high regard, but he is making a huge mistake as united have also got young strikers ahead of him in the pecking order. What is he thinking!