Se rifiuti il mio aiuto, almeno dimmi che cosa ti serve davvero.

Rifiuti is the second-person singular present form of rifiutare: you refuse.

So:

• io rifiuto = I refuse
• tu rifiuti = you refuse
• lui/lei rifiuta = he/she refuses

One thing that can confuse learners is that rifiuti also looks like the present subjunctive form. In this sentence, though, after se, it is understood as the present indicative because this is a normal, real condition: If you refuse my help...

Because this sentence is talking about a real or possible condition, not a hypothetical or impossible one.

A very common Italian pattern is:

• se + present indicative, then
• present, future, or imperative in the main clause

So here:

• Se rifiuti il mio aiuto = If you refuse my help
• dimmi... = tell me...

That combination is completely normal in Italian.

Compare:

• Se vieni, ti aiuto. = If you come, I’ll help you.
• Se hai tempo, chiamami. = If you have time, call me.

If the idea were unreal or contrary to fact, Italian would use a different structure.

In Italian, possessives usually go with a definite article:

• il mio libro = my book
• la tua macchina = your car
• il nostro aiuto = our help

So il mio aiuto is the normal form.

English often says just my, but Italian usually wants both:

• article + possessive + noun

A famous exception is with many close family singular nouns:

• mia madre
• tuo fratello

But aiuto is not one of those exceptions, so il mio aiuto is correct.

Almeno means at least.

It sets a minimum request:

• If you refuse my help, at least tell me what you really need.

So the speaker is saying something like:

• maybe you do not want my help, fine
• but at minimum, tell me what you actually need

It can make the sentence sound a little more natural and emotionally nuanced. Without almeno, the sentence would be more direct and slightly harsher.

Dimmi is the informal singular imperative of dire with the pronoun mi attached.

Breakdown:

• dire = to say / to tell
• imperative of dire for tu = di’
• di’ + mi = dimmi

In affirmative commands, object pronouns are usually attached to the end of the verb:

• dimmi = tell me
• dammi = give me
• portami = bring me

So dimmi is the natural way to say tell me when speaking to one person informally.

Mi dici would mean you tell me / will you tell me, not a direct command in the same way.

Yes. Che cosa here means what.

In this sentence, it introduces an indirect question:

• dimmi che cosa ti serve
• literally: tell me what you need

Italian has a few common ways to say what:

• che cosa
• cosa
• sometimes just che in informal speech

So all of these are possible in many contexts:

• Dimmi che cosa ti serve.
• Dimmi cosa ti serve.

Che cosa sounds a bit fuller or slightly more explicit, but it is very common and natural.

Because servire in this kind of sentence does not mean to serve in the restaurant sense. It means something like:

• to be needed
• to be useful
• to be necessary

The structure works like this:

• the person who needs something is expressed with an indirect object pronoun
• the thing needed is the grammatical subject

So:

• ti serve = is needed by/for you, or more naturally, you need
• mi serve = I need
• ci serve = we need

That is why ti appears, not tu.

Examples:

• Ti serve un consiglio? = Do you need some advice?
• Mi servono dei soldi. = I need some money.

In your sentence:

• che cosa ti serve davvero = what do you really need

Literally, it is closer to what is really needed by you.

Because the subject here is che cosa, and cosa is singular.

So:

• che cosa ti serve? = what do you need?

If the subject were clearly plural, the verb would be plural too:

• quali cose ti servono? = which things do you need?

This is one reason che cosa ti serve is such a common fixed pattern.

Davvero means really, truly, or actually.

At the end of the sentence, it emphasizes the real need:

• what you really need
• not what you say casually
• not what seems obvious
• but what you actually need

Putting davvero at the end is very natural in Italian and gives it emphasis.

Compare:

• che cosa ti serve davvero = what you really need
• davvero highlights sincerity or the true situation

It is informal singular.

You can tell from:

• rifiuti = you for tu
• dimmi = tell me, addressed to tu
• ti = to you, informal singular

So the speaker is talking to one person in an informal way.

A formal version would be something like:

• Se rifiuta il mio aiuto, almeno mi dica che cosa Le serve davvero.

That would be used with Lei.

Yes, absolutely.

Both are natural:

• Dimmi che cosa ti serve davvero.
• Dimmi cosa ti serve davvero.

In everyday speech, many speakers would probably prefer the shorter cosa version, but che cosa is perfectly standard and common.

So for a learner, the safest idea is:

• che cosa = correct and common
• cosa = also correct and very common

Because the sentence begins with a conditional clause:

• Se rifiuti il mio aiuto = If you refuse my help

Then the main clause follows:

• almeno dimmi che cosa ti serve davvero = at least tell me what you really need

Italian often uses a comma after an initial se clause, just like English often does after an opening if clause. It helps separate the two parts clearly.