According to this Medium article and this Vox article Donald Trump made campaign contributions to two attorneys general who then suddenly decided to stop investigating his "Trump University" for fraud.
Is this true?
There are two incidents: one in Florida and one in Texas where Trump (or, more accurately, the Trump Foundation) made campaign contributions conspicuously around the time the investigations or suits were dropped.
The AP's story about Florida lays this out pretty clearly. A key bit:
The new disclosure from Attorney General Pam Bondi's spokesman to The Associated Press on Monday provides additional details around the unusual circumstances of Trump's $25,000 donation to Bondi. [...]
The money came from a Trump family foundation in apparent violation of rules surrounding political activities by charities. A political group backing [Attorney General Pam] Bondi's re-election, called And Justice for All, reported receiving the check Sept. 17, 2013 — four days after Bondi's office publicly announced she was considering joining a New York state probe of Trump University's activities, according to a 2013 report in the Orlando Sentinel.
After the check came in, Bondi's office nixed suing Trump, citing insufficient grounds to proceed.
This does not seem unusual for Trump, who was quoted as saying:
I give to everybody. When they call, I give...You know what? When I need something from them, two years later, three years later, I call them, and they are there for me.
The AP story about the Texas case is similar, but differs in that the money came shortly after the inquiry was dropped. Key quote:
Besides the probe that led to Attorney General Schneiderman's suit in New York, the office of then-Texas Attorney General Greg Abbott, a Republican, opened a civil investigation of "possibly deceptive trade practices." Abbott's probe was quietly dropped in 2010 when Trump University agreed to end its operations in Texas. Trump subsequently donated $35,000 to Abbott's successful gubernatorial campaign, according to records.
It should be noted that this is circumstantial evidence. It is pretty convincing, but there is no smoking gun.