I believe that there are two possibilities here. The first (which I consider more likely) is that the interviewer means "only". In the previous sentence, the interviewer said "that wasn't a question", so he or she is suggesting that the current sentence "only" means what it says and doesn't have any other purpose (such as asking a question). Merriam-Webster has the following definition:

3a: ONLY, SIMPLY
| just last year
| just be yourself

The interviewer might also be using "just" for emphasis, in which case it would be similar to "really". The Collins Dictionary says:

You use just to emphasize the following word or phrase, in order to express feelings such as annoyance, admiration, or certainty.
[emphasis]
She just won't relax.
I knew you'd be here. I just knew.
Isn't it fantastic? Just look at that!
Just think, we should be home this time tomorrow.
I don't see the point in it really. It's just stupid.
Isn't he just the most beautiful thing you ever saw?

I believe that there are two possibilities here. The first (which I consider more likely) is that the interviewer means "only". In the previous sentence, the interviewer said "that wasn't a question", so he or she is suggesting that in the current sentence "only" means what it says and doesn't have any other purpose (such as asking a question). Merriam-Webster has the following definition:

3a: ONLY, SIMPLY
| just last year
| just be yourself

The interviewer might also be using "just" for emphasis, in which case it would be similar to "really". The Collins Dictionary says:

You use just to emphasize the following word or phrase, in order to express feelings such as annoyance, admiration, or certainty.
[emphasis]
She just won't relax.
I knew you'd be here. I just knew.
Isn't it fantastic? Just look at that!
Just think, we should be home this time tomorrow.
I don't see the point in it really. It's just stupid.
Isn't he just the most beautiful thing you ever saw?