İnandırıcı görünmesi doğru olduğunu kanıtlamaz.

It breaks down like this:

• inandırıcı = convincing, persuasive, believable
• görünmesi = its seeming / its appearing
• doğru olduğunu = that it is true
• kanıtlamaz = does not prove

So the whole sentence is literally something like:

Its seeming convincing does not prove that it is true.

A more natural English translation would be:

Just because it seems convincing doesn't prove it's true.

Because Turkish often turns verbs into noun-like clauses.

• görünmek = to seem / to appear
• görünmesi = its seeming / the fact that it seems

Here, görünmesi is functioning as the subject of the sentence. Turkish often uses this -mA + possessive form to make a clause behave like a noun.

So:

• İnandırıcı görünmek = to seem convincing
• İnandırıcı görünmesi = its seeming convincing / the fact that it seems convincing

In this sentence, görünmesi makes the idea more noun-like and more suitable as the subject of kanıtlamaz.

The -si is the 3rd person singular possessive ending.

So:

• görünme = seeming, appearing
• görünmesi = its seeming / his-her-its seeming

This does not always need to refer to a clearly stated his/her/its in English. In Turkish, this kind of possessive marking is very common in subordinate clauses.

Here it roughly points to the thing being discussed:

• onun inandırıcı görünmesi = its appearing convincing

Turkish often leaves that onun unstated if it is understood from context.

Doğru olduğunu means that it is true.

It comes from:

• doğru = true, correct
• olduğu = that it is / its being
• olduğunu = that it is, with accusative marking

This is a very common Turkish pattern for reported facts or embedded statements:

• biliyorum = I know
• doğru olduğunu biliyorum = I know that it is true

So in your sentence:

• doğru olduğunu kanıtlamaz = does not prove that it is true

Because it is the direct object of kanıtlamaz.

The verb kanıtlamak means to prove, and what is being proved here is:

• doğru olduğu = that it is true

As the direct object, it takes the accusative form:

• doğru olduğu → doğru olduğunu

So:

• Bir şeyi kanıtlamak = to prove something
• Doğru olduğunu kanıtlamak = to prove that it is true

Because Turkish often leaves pronouns out when they are understood from context.

English needs it:

• It seems convincing
• It is true

Turkish often does not state that pronoun separately. Instead, the reference is built into forms like:

• görünmesi = its seeming
• olduğunu = that it is

So the sentence does contain the idea of it, but not as a separate word.

İnandırıcı means convincing, believable, or persuasive.

It comes from the verb inandırmak, which means to convince or literally to make someone believe.

So:

• inandırmak = to convince
• inandırıcı = convincing

In this sentence, inandırıcı görünmesi means:

• its seeming convincing
• the way it appears convincing

It does not necessarily mean it really is true or reliable—only that it gives that impression.

Kanıtlamaz is the negative aorist in the 3rd person singular.

From:

• kanıtlamak = to prove
• kanıtlar = proves / does prove
• kanıtlamaz = does not prove

The Turkish aorist often expresses:

• general truths
• habitual actions
• broad statements
• definitions

That fits this sentence well, because it is stating a general principle:

Something's looking convincing does not prove it is true.

It can do either, depending on context, but it most naturally sounds like a general statement.

Because of the aorist form kanıtlamaz, it sounds like:

• Appearing convincing does not prove truth
• Just because something looks convincing, that doesn't make it true

If the context is about one specific thing, the sentence can still apply to that particular thing. Turkish often allows this kind of general-looking structure even when a specific example is meant.

Yes, you may hear or say:

İnandırıcı görünmek doğru olduğunu kanıtlamaz.

This is understandable and grammatical.

But görünmesi sounds a bit more like:

• its appearing convincing
• the fact that it appears convincing

So the version with görünmesi is slightly more noun-like and often feels more natural in formal or analytical statements.

Both are possible, but the original version has a more polished, subordinate-clause feel.

Because the sentence means that it is true, not its becoming true or its being made true.

Compare the two patterns:

• doğru olduğunu = that it is true
• doğru olmasını = its becoming true / for it to become true / its being true in a different grammatical frame

After kanıtlamak, Turkish usually uses the -DIK clause for factual content:

• Masum olduğunu kanıtladı. = He proved that he was innocent.
• Doğru olduğunu kanıtlamaz. = It does not prove that it is true.

So olduğunu is the correct and natural choice here.

Yes:

• İnandırıcı = convincing
• görün-me-si = appear-VERBAL NOUN-3SG.POSS
• doğru = true
• ol-duğ-unu = be-SUBORDINATE CLAUSE FORM-3SG.POSS-ACC
• kanıtla-maz = prove-NEG.AOR.3SG

A very literal gloss would be:

Its appearing convincing does not prove its being true.

That is not natural English, but it shows the Turkish structure well.

The most important lesson is how Turkish expresses whole clauses as noun-like units.

This sentence has two embedded clauses:

1. İnandırıcı görünmesi
   = its seeming convincing
   → this is the subject

2. doğru olduğunu
   = that it is true
   → this is the object of kanıtlamaz

So Turkish is not just linking simple words here. It is using compact clause structures that English often translates with:

• that ...
• the fact that ...
• its ...-ing

If you get comfortable with forms like -mesi and olduğunu, sentences like this become much easier to read.