Mary is claiming in her book that Trump got someone else to sit his SATS test for him so that he could score enough points to get into Wharton College. The poster is making the point that she could not have first-hand knowledge of that. https://www.thewrap.com/mary-trumps-tell-all-book-president-cheated-on-sats-commented-on-nieces-breasts-abandoned-brother-on-deathbed/