【Undertale】The truth in sans' room (Spoilers)

EDIT: A continuation of this can be found here: • 【Undertale】WHO GOT OWN...
I've been playing Undertale like crazy, it's so fun, I highly recommend it. If you reload and speak to sans three times in the judgement hall, you can get a key to san's room, and he mentions you'll discover the "truth"
Well...I wasn't very happy.
EDIT: I know about the shed, this is just funnier