All this means is that they is at least a 50% chance that a crime was committed. In a grand jury the defendant isn't allowed to be present and can't present evidence. Only the prosecution puts on a case. So being indicted is standard run of the mill procedure.
Finding a person guilty at court is however very difficult - beyond a reasonable doubt - and the defendant get's to put on a defense.
Also under the constitution a person has a right to a speedy trial - if the right to a speedy trial is not waived the case has to be wrapped up within 6 months from the time a person is officially charged, in this case indicted.