Learn Hardcore French: Sans reçu, il est difficile de prouver l’achat. - Without a receipt, it is difficult to prove the purchase.

After sans, French often omits the article to talk about something in general: sans reçu = without a receipt (in general).
sans un reçu is possible but adds emphasis: without a single receipt/any receipt at all.
sans le reçu points to a specific, known receipt (the one for this purchase).
All are correct; choose based on meaning:
- Sans reçu, il est difficile de prouver l’achat.
- Sans un reçu, il est difficile de prouver l’achat. (emphasis)
- Sans le reçu, il est difficile de prouver l’achat. (the specific receipt)

Can I move sans reçu to the end?

Yes. Il est difficile de prouver l’achat sans reçu. This is very natural. The initial comma in the original simply sets off the fronted phrase; it’s optional when you move it.

What’s the difference between il est difficile de and c’est difficile de?

Il est + adjective + de + infinitive is the standard impersonal construction; neutral to formal.
C’est + adjective + de + infinitive is more conversational.
Both are correct here:
- Il est difficile de prouver l’achat.
- C’est difficile de prouver l’achat.

Why de before prouver and not à?

With the impersonal pattern il est + adjective + de + infinitive, you use de. Use à when the adjective directly modifies a specific noun:

Impersonal: Il est difficile de prouver l’achat.
With a noun subject: Cette accusation est difficile à prouver. Avoid: Il est difficile à prouver l’achat. (ungrammatical)

Can I say difficile à prouver here?

Not after impersonal il est.
You can say it if you give the adjective something to modify:
- C’est difficile à prouver.
- Ce crime est difficile à prouver.

Where does a pronoun go if I replace l’achat with le?

Object pronouns go before the infinitive:

Sans reçu, il est difficile de le prouver. Similarly: Sans reçu, il est difficile de la prouver. (if the object were feminine)

What is reçu here: noun or verb form? Spelling, gender, plural?

Here reçu is a common noun meaning “receipt.”
Spelling: reçu with a cedilla (ç) to keep the s sound before u; no accent on the u.
Gender and plural: un reçu (masc.), plural des reçus.
It’s homographic with the past participle of recevoir (reçu = “received”), but context tells you it’s a noun here.

Why is there an apostrophe in l’achat?

It’s the elision of the definite article le before a vowel sound: le + achat → l’achat. The h in achat is silent (h muet), so elision applies.

Why not prouver de l’achat?

Because prouver takes a direct object: prouver quelque chose. So you say prouver l’achat. You use de in a different noun phrase: une preuve d’achat (proof of purchase).

How do you pronounce the tricky parts?

sans: SAHN (nasal vowel; final s silent; liaison only before a vowel: sans argent → [z] sound).
reçu: roughly ruh-SUE; ç = s sound; u is the French front rounded vowel (like German ü).
l’achat: la-SHA; ch = sh; final t silent; elision makes l’ flow into achat.
No mandatory liaison in prouver l’achat; careful speech may link, but everyday speech often doesn’t.

Does this structure require the subjunctive?

No. Il est difficile de + infinitive uses the infinitive. If you used a que-clause, you could get the subjunctive: Il est difficile que cela se produise, but that’s a different structure.

Can I make reçu plural? When would I say sans reçus?

Yes: reçus. Use sans reçus when you mean “without receipts” (plural), e.g., for multiple transactions. For emphasis on having none at all, you can say sans aucun reçu.

What’s the difference between reçu and facture?

reçu: receipt given after payment; proof you paid.
facture: invoice/bill requesting payment; you usually get it before or at the time of paying. So proving a purchase often relies on a reçu or other preuve d’achat.

Is the comma after Sans reçu necessary?

No. It’s stylistic. With the phrase at the start, many writers add a comma: Sans reçu, il est… Without it is also acceptable. At the end, no comma is needed: … prouver l’achat sans reçu.

Could I also say Sans preuve d’achat?

Yes, very idiomatic: Sans preuve d’achat, il est difficile de prouver l’achat. More naturally, you’d complete it with what’s hard to do, e.g., Sans preuve d’achat, il est difficile d’obtenir un remboursement.