Is there a trope for this, and if not why not?

okay, so this one is kind of infrequent but it's still a recurring plot element: a character wants to become stronger for whatever reason and seeks out a retired warrior who is at first reluctant to train them but eventually warms up to it. i looked around for this before but couldn't find it anywhere in the trope lists. i even have two examples of this to start us off if there's no trope page for it:

— in "Sword of the Samurai" by Eric A. Kimmel, in the chapter "Matajuro's Training", the arrogant samurai's son Yagyu Matajuro angers all his potential teachers such that no one will train him until he goes to a man named Banzo, who at first either doesn't notice him or pretends that he isn't there until Matajuro has been at his front door for a month, after which he finally starts training him. — in "Assassin's Creed III", Ratonhnhaké:ton goes to Achilles Davenport when he learns from Juno that he needs to find the Assassins, and Achilles refuses to train him until Ratonhnhaké:ton defends the homestead from interloping colonists.

so, anyone?

Might want to ask in Lost And Found, there.