I think we can use Usopp, as a good example, since Oda also likes to use Usopp as the most "realistic" person on the crew.
He faced very dangerous situations in Paradise and even East Blue, like when he and Chopper fought Mr. 4 and Miss Merry Christmas. Usopp, who was just a skinny kid, was wrecked at the end of that fight while on the other side of town Zoro, a dude who trained all his life, awoke haki. Then after a couple of years training his body and his mind on a dangerous island Usopp was in an impossible situation, not even about his life directly but about his friend and captain, and he awoke his haki.
You need not only the drive but you also to be tough. And if you have enough drive you end up becoming though enough.