This is close to some of the existing answers, but seems to be a slightly different tack than most are suggesting.
You were told to expect a pay increase by the recruiter when you were hired, once you were out of the probation period. You're out of the probation period, but you've gotten no pay increase.
There are several possibilities here, not all of which have been noted elsewhere:
- The recruiter knowingly or unknowingly lied, and that's not how this job works;
- Your boss is trying to get away with not giving you the increase;
- Your company has some sort of wage/salary freeze on, so no one's getting increases right now;
- You should have gotten the increase, and there's been some snag in the process so it has gotten through (anything from the boss legitimately forgetting, to a snafu in HR, etc.);
- As far as your boss is concerned, you haven't completed the probationary period.
In any job where there was some sort of probationary period, I generally had a meeting with my boss when that period was over, confirming I had successfully completed it and was off probation. And, at that point, if there was a salary increase involved, I'd be told that was going through as well. If that hasn't happened, that last possibility is one to consider.
It's entirely legitimate to talk to your boss for a clarification of the current situation. Are you officially considered off probation? Was the information provided by the recruiter false? Should you have gotten a salary increase?
If the recruiter is giving new hires false information your company would want to know. They probably paid that recruiter to find you; if what the recruiter says makes new hires less likely to stick around because they feel they're not getting what was promised, they're going to want to bring that up with the recruiter.
If a legitimate mistake happened, your boss is going to want to know. For that matter, if your boss was trying to get away with something, this gives them an out; they don't have to say they were trying to screw you over, they can say it was a mistake.
If there's a freeze on salary increases, your boss probably wants you to know that; if you hang in, you'll (theoretically) be paid what you're "worth". No guarantee that's true, but odds are in any reasonably large firm that the situation would be announced.
Finally, if you're not off probation, you want to know. Was the probation period longer than you thought? Has some perceived problem caused them to extend it? If they aren't actually happy with you, you want to know why and what you can do about it; and, maybe, you want to keep your eyes and ears open for other opportunities (or even actively seek another job).
I'd go to the boss on the assumption that the situation may be different than you think, just looking to understand the way things are actually done in the company. You don't have to propose a reason why things are not the way you were lead to believe; just explain what your understanding initially was, and ask how things actually work.