Almost everyone around him says it way before the Q drop in 2019… then the President adopts it as a campaign mantra and you call that a proof?
Your bar for proofs is low and this "proof" is not convincing. You have to do better than that.
https://gop.com/icymi-lara-trump-the-best-is-yet-to-come
https://www.newsmax.com/politics/pence-texans-tax/2018/02/16/id/843788/
https://dunn.house.gov/2018/1/congressman-dunn-the-best-is-yet-to-come
And even Obama said it….
https://www.wsj.com/video/obama-victory-speech-the-best-is-yet-to-come/46D71010-A175-4E89-9D03-F760DE884ABF.html