Я искренне благодарен тебе за поддержку.

Благодарен is a short-form adjective, not a verb. It means grateful rather than I thank.

So:

• Я благодарю тебя = I thank you
• Я благодарен тебе = I am grateful to you

In this sentence, Russian expresses a state/feeling: I am sincerely grateful to you for the support.

Short-form adjectives are very common after я / ты / он / она when describing a temporary or current state.

In the present tense, Russian usually omits the verb to be.

So:

• Я искренне благодарен тебе literally looks like I sincerely grateful to-you
• but it means I am sincerely grateful to you

This is completely normal in Russian.
If you wanted the past or future, forms of to be would appear differently:

• Я был благодарен = I was grateful
• Я буду благодарен = I will be grateful

Because благодарен takes the person you are grateful to in the dative case.

The pronoun ты changes like this:

• ты = you (subject)
• тебе = to you

So:

• Я благодарен тебе = I am grateful to you

This is similar to English to you, even though English often leaves out to in some contexts.

The preposition за here means for, and after за in this meaning, Russian uses the accusative case.

• поддержка = support
• accusative singular: поддержку

So:

• за поддержку = for the support / for your support

This pattern is very common:

• Спасибо за помощь = Thanks for the help
• Благодарен за совет = Grateful for the advice
• Спасибо за поддержку = Thanks for the support

Искренне is an adverb, meaning sincerely.

It describes how the speaker feels grateful:

• искренне благодарен = sincerely grateful

Compare:

• искренний = sincere (adjective, used with nouns)
  • искренний человек = a sincere person
• искренне = sincerely (adverb)
  • искренне благодарен = sincerely grateful

You may also encounter искренно, but искренне is the standard and more common modern form here.

Yes. Благодарен is masculine singular.

If the speaker is female, she would say:

• Я искренне благодарна тебе за поддержку.

So:

• благодарен = said by a man
• благодарна = said by a woman

This is an important feature of Russian: adjectives and short-form adjectives often show gender.

It is emotionally sincere and can work in both neutral and somewhat formal contexts, but тебе makes it informal singular because it uses ты.

If you want to address someone formally or more politely, use Вам:

• Я искренне благодарен Вам за поддержку.

So:

• тебе = to you, informal singular
• Вам = to you, formal singular or plural

The phrase itself sounds a bit more heartfelt and weighty than a simple Спасибо.

Спасибо за поддержку means Thanks for the support and is very common, natural, and simple.

Я искренне благодарен тебе за поддержку is:

• more personal
• more explicit
• more emotional
• slightly more formal or literary in tone

It emphasizes a genuine feeling of gratitude, not just a routine thank-you.

So the difference is roughly:

• Спасибо за поддержку = Thanks for the support
• Я искренне благодарен тебе за поддержку = I am sincerely grateful to you for the support

Yes. Russian word order is fairly flexible, though different orders can shift emphasis.

The original:

• Я искренне благодарен тебе за поддержку.

Other possible versions:

• Я тебе искренне благодарен за поддержку.
• Тебе я искренне благодарен за поддержку.
• За поддержку я искренне благодарен тебе.

All are understandable, but the original sounds natural and neutral.

Very roughly:

• putting тебе earlier can emphasize to you
• putting за поддержку earlier can emphasize for the support

Yes. In Russian, possession is often understood from context and does not have to be stated.

So за поддержку can naturally mean:

• for the support
• for your support

If needed, Russian can be more explicit:

• за твою поддержку = for your support
• за Вашу поддержку = for your support (formal)

But in many situations, just за поддержку sounds perfectly natural.

The main stress pattern is:

• Я искре́нне благода́рен тебе́ за подде́ржку.

Useful notes:

• искре́нне — stress on -кре́-
• благода́рен — stress on -да́-
• тебе́ — stress on the last syllable
• подде́ржку — stress on -де́р-

Correct stress matters in Russian, because it is not always predictable.

Yes, absolutely.

• очень благодарен = very grateful
• искренне благодарен = sincerely grateful

Both are natural, but they are slightly different in tone:

• очень emphasizes degree
• искренне emphasizes genuineness

You can even combine them:

• Я очень искренне тебе благодарен за поддержку — possible, though a bit heavier stylistically
• more natural: Я тебе очень благодарен за поддержку
• or Я искренне тебе благодарен

Yes. It is very useful to remember this structure:

• [someone] благодарен / благодарна [dative] за [accusative]

For example:

• Я благодарен вам за помощь. = I am grateful to you for the help.
• Она благодарна ему за совет. = She is grateful to him for the advice.
• Мы благодарны тебе за всё. = We are grateful to you for everything.

So this sentence is a great model for building similar expressions.