I have a 45" bust. This hoodie is, according to the size chart, theoretically 46" across the bust. So it should be about right, right- However, it fits like a circus tent on me. Genuinely too big to wear by multiple sizes. I'd buy a medium if I was inclined to re-purchase one that fits and I could probably get away with a small.
The quality seems good–it's a nice thin hoodie with a lot of give, so if you're between sizes you could safely size down, but do not (like me) take the size chart as gospel. It's completely wrong (as are all Jinx clothing size charts, to be fair, and I knew this, but for whatever reason I trusted this one).