Like others, I too am happy the club is taking the stance that they won't waste too much time trying to convince De Jong to join if he is particularly unwilling to move to United. What I don't understand is that some people would turn him down just because he requires any convincing in the first place.
What must be taken into consideration here is that De Jong is not a Manchester United fan. He doesn't feel the same way we do about the club; when he looks at us, his first impression a side that is an absolute mess competing outside of the Champions League next season. Frankly, I'd be more concerned if he didn't require some convincing to join us, as I'd assume he was just joining for the money.
I understand people are worried about another Di Maria situation but you have to take into consideration that Di Maria was essentially signed just because he was a big name available to appease the fans, without any consideration for how he'd fit into the manager's system. What a lot of people fail to mention when bringing up the Di Maria fiasco is that he was benched for Ashley Young within about five months of joining because his cavalier, risk-reward playing style didn't fit with the more rigid style than Van Gaal implemented at United. This almost certainly would not happen with De Jong. There perhaps isn't a manager more qualified to bring the best out of him than Erik ten Hag, and if De Jong were to join United he would almost certainly become the key midfielder immediately.
Ultimately, I feel that if De Jong were to sign for United and played in a system that allowed him to flourish whilst also regularly making the Champions League and eventually even competing for trophies, he'll probably end up happy here even if he was initially reluctant to join. That's why I think the question we need to be asking is not "Is this going to be another Di Maria?" but rather "Is this going to improve the long-term prospects of the club?"