Macbook hangs at startup
How long have you left it at that point?  Another user reports the same issue, but they left it for another 15-20 minutes and then another message appeared highlighting a disk failure.

Try creating a bootable back up on an external drive ASAP and test it.  Then at your leisure investigate further, that is leaving it on the start up verbose message screen.

I personally would recommend using carbon copy cloner as it was quite useful, but super duper has a free mode that should work for you.