Gov. Ron DeSantis, a man Mr. Trump believes he put on the map, has been acting far less like an acolyte and more like a future competitor, Mr. Trump complains. With his stock rising fast in the party, the governor has conspicuously refrained from saying he would stand aside if Mr. Trump runs for the Republican nomination for president in 2024.

“The magic words,” Trump has said to several associates and advisers…

[T]he 43-year-old DeSantis … has told friends he believes Mr. Trump’s expectation that he bend the knee is asking too much. That refusal has set up a generational clash and a test of loyalty in the de facto capital of today’s G.O.P., one watched by Republicans elsewhere who’ve ridden to power on Mr. Trump’s coattails…

“I wonder why the guy won’t say he won’t run against me,” Mr. Trump has said to several associates and advisers, who spoke on condition of anonymity to describe private conversations.