İltifatın cidden çok güzeldi.

İltifatın is iltifat + -ın.

• iltifat = compliment
• -ın = your (2nd person singular possessive suffix)

So iltifatın means your compliment.

This is very common in Turkish: instead of using a separate word like your, Turkish often adds a suffix directly to the noun.

Because Turkish often leaves out the separate possessor pronoun when it is not needed.

Both of these are possible:

• İltifatın cidden çok güzeldi.
• Senin iltifatın cidden çok güzeldi.

They both mean roughly the same thing: Your compliment was really very nice.

Adding senin makes your more explicit or slightly more emphatic. Without senin, the sentence still sounds completely natural.

Yes, in some contexts -ın can also be the genitive ending, so iltifatın could theoretically mean of the compliment.

But in this sentence, it is understood as your compliment because of how it functions in the sentence:

• İltifatın = the subject
• güzeldi = was nice

So here the natural reading is clearly your compliment was very nice.

Because güzeldi means was nice/beautiful/lovely.

It breaks down like this:

• güzel = nice, beautiful
• -di = past tense form of to be

So:

• güzel = nice
• güzeldi = it was nice

Turkish often attaches the equivalent of was/were directly to adjectives and nouns.

Yes, but it is built into güzeldi.

In English, you say:

• Your compliment was very nice.

In Turkish, the was part is attached to the adjective:

• güzel-di

So the sentence does have a verbal idea, but it appears as a suffix rather than as a separate word.

They intensify the sentence in slightly different ways:

• cidden = really / genuinely / seriously
• çok = very

So cidden çok güzeldi means something like:

• really very nice
• genuinely very nice

Using both together adds emphasis. It sounds natural and expressive.

A natural interpretation is:

• İltifatın = topic/subject: your compliment
• cidden çok = intensifier: really very
• güzeldi = main comment: was nice

So the sentence focuses on the judgment that the compliment was especially nice.

Depending on intonation, a speaker could emphasize different parts:

• İLTİFATIN cidden çok güzeldi.
  = It was your compliment that was really nice.
• İltifatın CİDDEN çok güzeldi.
  = It was really very nice.
• İltifatın cidden çok GÜZELDİ.
  = It really was very nice.

Güzel often means beautiful, but it is also used much more broadly than English beautiful.

Depending on context, güzel can mean:

• beautiful
• nice
• lovely
• good
• pleasant

With iltifat (compliment), güzel naturally means something like:

• nice
• lovely
• sweet

So İltifatın cidden çok güzeldi is a very natural way to praise someone's compliment.

Turkish word order is more flexible than English, but a very common neutral order is:

subject + adverb(s) + predicate

So here:

• İltifatın = subject
• cidden çok = adverbial intensifiers
• güzeldi = predicate

This makes the sentence completely natural in Turkish.

English also puts the verb was separately, while Turkish attaches that meaning to the predicate.

Yes. That would be perfectly natural.

• İltifatın çok güzeldi. = Your compliment was very nice.
• İltifatın cidden çok güzeldi. = Your compliment was really very nice.

Adding cidden makes it stronger and more heartfelt.

Yes, very often.

• İltifatın gerçekten çok güzeldi.
• İltifatın cidden çok güzeldi.

Both are natural and mean roughly Your compliment was really very nice.

A small nuance:

• gerçekten can feel a bit more standard or neutral
• cidden can feel a bit more conversational

But both are common and correct.

It is basically neutral to slightly warm/conversational.

• iltifat is a normal standard word
• cidden is common in spoken Turkish
• the whole sentence sounds friendly and natural

It works well in everyday conversation. In a more formal style, someone might prefer gerçekten instead of cidden, but the sentence itself is not rude or slangy.

A rough guide:

• İltifatın ≈ eel-tee-FAH-tuhn
• cidden ≈ jid-DEN
• çok ≈ chok
• güzeldi ≈ gyu-ZEL-dee

A few helpful notes:

• ç = ch
• c = j as in jam
• ü is a front rounded vowel, not exactly like English oo
• ı is the Turkish dotless i, a vowel that does not exist exactly in English

A natural rhythm would be:

İltifatın cidden çok güzeldi.

with a smooth rise toward çok and the statement landing on güzeldi.

Yes. Even if the basic meaning is already clear, here are some natural English-style renderings:

• Your compliment was really very nice.
• That was a really nice compliment.
• Your compliment was so nice.
• That was genuinely such a nice compliment.

The exact English version depends on tone, but the Turkish structure stays the same.