Should I be upset if my bf tweets "marry me Victoria" on his twitter page and then denies it's him? And, she replies in under a hour...

Can you actually prove it was him that wrote it and not a friend being funny on his phone?  If not then give him the benefit of the doubt and make up. This is exactly why the courts hate using cell phones as evidence for texts as there is now way to prove 100% who actually wrote and sent it no matter whos phone it is