Ik bewaar de bon.

Because the subject is ik (I).

In the present tense, Dutch usually uses:

• ik bewaar = I keep
• jij bewaart / u bewaart = you keep
• hij/zij bewaart = he/she keeps

So with ik, the verb normally takes the stem without -t.

The infinitive is bewaren.
Its stem is bewaar-, so:

• ik bewaar
• jij bewaart
• hij bewaart

It follows the normal Dutch main-clause order:

subject + verb + object

• Ik = subject
• bewaar = verb
• de bon = object

So it is very similar to English I keep the receipt.

Bewaren usually means to keep, to save, or to store.

In a sentence like Ik bewaar de bon, it often means:

• I keep the receipt
• I save the receipt
• I hold on to the receipt

It suggests not throwing it away, often in case you need it later.

Because bon is a de-word in Dutch.

Dutch nouns take either:

• de
• het

You generally have to learn this with each noun.
Here it is:

• de bon = the receipt

So you would also say:

• een bon = a receipt

In this sentence, bon means receipt.

Depending on context, bon can also mean things like:

• voucher
• coupon
• ticket/slip

But in everyday shopping situations, de bon very often means the receipt.

De means the, so de bon refers to a specific receipt.

That usually means the speaker and listener both know which receipt is meant, for example the one from a purchase that just happened.

Compare:

• Ik bewaar de bon. = I’m keeping the receipt.
• Ik bewaar een bon. = I’m keeping a receipt.

The second one sounds less specific.

Yes. Dutch present tense often covers both:

• I keep the receipt
• I am keeping the receipt
• I will keep the receipt

The exact meaning depends on context.

So Ik bewaar de bon can easily be used when someone has just bought something and means I’ll keep the receipt.

You add niet:

• Ik bewaar de bon niet.

This means I’m not keeping the receipt.

In a simple sentence like this, niet usually goes near the end.

In Dutch yes/no questions, the verb usually comes first:

• Bewaar ik de bon?

That is the literal question form: Am I keeping the receipt? or Should I keep the receipt? depending on context.

Very often in real conversation, you might hear:

• Bewaar je de bon? = Are you keeping the receipt?

So the main pattern is verb + subject + object.

Yes.

Because bon is a de-word, the object pronoun is usually hem:

• Ik bewaar hem. = I’m keeping it.

That said, in everyday speech, people sometimes avoid the pronoun and just repeat the noun if that is clearer.

Not exactly.

Bewaren means keep/save/store in the sense of not throwing something away or keeping it for later.

Houden is much broader and can mean things like:

• to hold
• to keep
• to like

For a receipt, bewaren is the natural choice:

• Ik bewaar de bon.

That means you are keeping it safely for later use, for example for returns or warranty.

A simple approximation is:

• Ik ≈ ik
• bewaar ≈ buh-VAHR
• de ≈ duh
• bon ≈ bon with a short o

A few useful notes:

• bewaar has the stress on the second part: beWAAR
• Dutch w is not exactly like English w; it is closer to a soft v/w sound
• bon has a short vowel, not a long English o

The infinitive is bewaren.

So:

• bewaren = to keep / to save
• ik bewaar = I keep
• jij bewaart = you keep
• wij bewaren = we keep

Learning the infinitive helps you recognize the verb in dictionaries and grammar tables.

Yes. In a subordinate clause, Dutch usually puts the conjugated verb later, often at the end.

Main clause:

• Ik bewaar de bon.

Subordinate clause:

• ... omdat ik de bon bewaar. = ... because I keep the receipt.

So the meaning stays the same, but the word order changes.