Citizen Applicantion denied admitting a crime

I have a friend who's been working in Japan and she plans to aplly for citizenship. The problem is that she didnt experience being convicted once but has tried Marijuana. Not admitting this I think can create another crime so she's thinking that she will admit it during the interview, but that's why shes worried, because she might get denied.
Is it possible for her application to be successful or not? And another thing, Will she be sent back to the country where she's from after they denied it or not?

As you or your "friend" might know that Japan is very strict on drug related offence.
A conviction will most probably automatically get the application denied.

Using but non-conviction, then depends on the interview and how the answer go.
Best is to answer only what been asked, so in a way you are not 'lying' if you answer the interview correctly.

However, they will also do background check in addition to interview so what goes around comes around.
So it is up to the applicant how to go about their application.

Was your friend caught by the police using marijuana and wasn't charged or convicted? Or is this a case of she tried marijuana once and no authorities know?

If she was never charged or convicted then why would she admit to it?

If "your friend" just tried it once. And has no conviction. Why would you need to admit to it? Serious, why is it so difficult for adults to be adult these days?

No conviction no problem. If your so called friend as been imprisoned more than 6 months than it will be another story. Japan is not keen on drugs and punishment is heavy.

First do not lie on the application, because even when your so called friend has a citizenship it can be revoked. Also lying on the application gives other problems. If there is only a fine, then there is no need to mention, since this is register as a crime, of course it depends where your so called friend is coming from.

Is there any evidence that your friend tried it? No evidence? No problem.

Thank you for the answers. My friend is very worried because a lot of people know her and someone might bring up that she tried it cause shes pretty famous YouTuber and yeah might get deported when they found out. Anyways thanks for the answers I think ill just advice her to go home cause its going to be hard for her. Thank you for the answers