sinsa ni goukakusita monono, toraiarukikan ha mada hazimatte inai.

ものの means something like although, even though, or while it is true that....

In this sentence:

• 審査に合格したものの
• Although [someone] passed the screening/examination...

It introduces a contrast between two facts:

• passing the screening
• the trial period still not having started

Compared with other contrast words:

• けど / けれども: more common in everyday speech, often softer and more casual
• が: also means but, often a bit more neutral or formal
• ものの: more literary, formal, or stiff, and often emphasizes that the second part is contrary to what you might expect from the first

So passed the screening, but the trial period still hasn’t started is the basic idea, but ものの gives it a slightly more formal and explanatory tone.

The verb 合格する normally takes に, not を, for the exam/test/screening that is passed.

So:

• 試験に合格する = to pass the exam
• 審査に合格する = to pass the screening/review

This is just the standard pattern for this verb.

A rough way to think about it is:

• Xに合格する = to succeed in / pass X

Using を with 合格する is not standard here.

審査 means a screening, review, evaluation, or judging process, depending on context.

It is broader than a normal school-style exam. For example, it could refer to:

• an application review
• an audition screening
• a document check
• a qualification review
• some kind of selection process

So in this sentence, 審査に合格した means the person passed some kind of evaluation or selection stage.

In this grammar pattern, ものの is usually written in hiragana because it functions as a grammatical expression, not as the regular noun 物 meaning thing.

So here:

• ものの is a fixed conjunctive expression
• it does not literally mean thing + of

That is why learners usually just memorize ものの as a grammar pattern meaning although / but even so.

は marks トライアル期間 as the topic:

• トライアル期間はまだ始まっていない
• As for the trial period, it still hasn’t started

Using は helps set up a contrast or focus:

• the screening was passed
• but the trial period, as for that, has not started yet

This works especially well after ものの, because the whole sentence is presenting contrasting information.

If が were used instead, the nuance would be a little different, often sounding more like identifying the subject rather than setting it up as the topic/contrast. Here, は is very natural.

With a negative verb, まだ means not yet.

So:

• まだ始まっていない = has not started yet

This is a very common pattern:

• まだ来ていない = has not come yet
• まだ食べていない = have not eaten yet
• まだ終わっていない = has not finished yet

Be careful not to interpret まだ by itself as simply still in every case. With a negative, not yet is usually the best translation.

始まっていない is the negative of 始まっている, and here it describes the current state:

• 始まっている = has started / is underway
• 始まっていない = has not started

This is different from:

• 始まらない = does not start / will not start / isn’t starting
• 始まらなかった = did not start

So まだ始まっていない focuses on the present situation:

• as of now, the trial period has not begun yet

That is why it fits well here.

Because the trial period is the thing that begins, not the thing that someone starts.

• 始まる = to begin, to start (intransitive)
• 始める = to start something (transitive)

So:

• トライアル期間が始まる = the trial period begins
• 会社がトライアル期間を始める = the company starts the trial period

In this sentence, the trial period itself is the subject/topic, so 始まる is correct.

トライアル期間 means trial period.

It is understandable Japanese and uses:

• トライアル = trial
• 期間 = period, term, duration

This kind of mixed katakana + kanji compound is very common in modern Japanese.

Depending on context, other expressions might also be used, such as:

• 試用期間 for an employment probation period
• お試し期間 for a free trial or trial-use period

But トライアル期間 is perfectly understandable, especially in business, services, apps, or modern casual contexts.

The subject is not explicitly stated, which is very normal in Japanese.

The sentence only clearly states:

• [someone] passed the screening
• the trial period has not started yet

Who that person is depends on context:

• I passed the screening...
• he/she passed the screening...
• they passed the screening...

Japanese often leaves out subjects when they are already understood from the situation.

Often, yes—at least some sense of unexpected contrast.

The structure suggests:

• normally, if you pass the screening, you might expect the next stage to begin
• however, that expected next step has not happened yet

So ものの can carry a nuance like:

• even though that happened, this other expected thing still hasn’t happened

It does not automatically mean strong disappointment, but it often sounds a bit like:

• despite that
• for all that
• and yet

That nuance is one reason ものの fits well here.

Yes. Here 合格したものの is not a noun phrase like the thing that passed. It is a fixed grammar pattern meaning although [someone] passed.

So the structure is:

• 審査に合格したものの、
• トライアル期間はまだ始まっていない。

This is a complete sentence with:

1. a subordinate concessive clause
2. a main clause

A learner might try to analyze もの literally as a noun, but in this pattern it is better to treat ものの as one grammatical unit.