The first element that can tell you whether or not you have succeeded in an individual job interview is the attitude of your interlocutor. What were his reactions? How did he behave? Obviously, you are not Madame Irma, and you do not have a gift for reading minds. But as in every exchange, there are signs that do not deceive! If he looks annoyed, rolls his eyes, or nods his head…that’s a pretty bad sign. If he doesn't ask you any questions, that's not necessarily a good sign either. He must show an interest in your background and your profile. If he looks at his watch a lot? Hard to say. He can be in a hurry and have files on fire. It's a bit like in any relationship:if the current has passed, you can feel it right away!
You have trained, you have prepared your job interview well, with research and role-playing. But did you manage to say everything you wanted to? It is important to convey messages to your interlocutor. The question is whether you come out of this individual interview frustrated. If so, you may not have argued enough. The other point is how long the interview with your recruiter lasted. If it's too short, less than ten minutes, that's a bad sign. On the other hand, if it lasted a little longer, and if a constructive discussion started between you, it is rather a good sign. But again, it's hard to know for sure if you've been successful. If the recruiter starts talking about the company and sells you its qualities, it seems to be really interested in your profile. You must never forget that the company must also seduce you!
It is extremely rare to know immediately if you are taken. It is often necessary to wait a few days, sometimes even a few weeks. Individual interviews usually end with the famous "we'll call you back" and "we'll take the time to think"! It is at this time very difficult to really know what the recruiter is thinking. However, if the latter asks you for documents or information to provide, it is a very good sign. Finally, if he accompanies you on the way out, it is also a positive element! In any case, you must always stay motivated and not sink into defeatism after a job interview. If we wanted to meet you, it is because your background and your profile are of interest! Never forget to believe in your qualities!