TRUST is a program written by David Boudreau (XSPR). He has graciously written up this article to help explain the program.
A few websites have offered various ways to get better at ST for some years now, such as Street Fighter Dojo which offers a comprehensive list of videos for any given character match-up; You browse to find a particular character’s match-up, and see what strategies and counters that some of the best players employ. There are also many tutorial videos available, demonstrating particular attacks or tactics like option selects or combos, with helpful features such as displaying inputs and replaying the tricky parts in slow-motion. Console ports of fighting games also have training modes.
Watching videos can give you an idea of what to do, but does not offer you the context of playing in an actual match to put it into practice and become familiar with actually Executing it.
While a training mode is the true test for self improvement for that shortcoming, no console port offers much in terms of features in this department to test the particular scenario you want to create (outside of very simple options such as making the dummy character jump straight up, crouch or block etc).
TRUST is a program designed to address this gap and lets you customize your own training mode particular to any given scenario that you want to practice. It even comes with a number of lessons built-in, which offer a kind of “missing manual” that never came with the game itself.