De her pensler er små, og de der ruller er bedre til den store væg.

They are demonstrative phrases:

• de her = these
• de der = those

Literally, they are built from:

• de = the plural determiner
• her = here
• der = there

So Danish often expresses these/those as something like the ones here / the ones there.

In this sentence:

• de her pensler = these brushes
• de der ruller = those rollers

This is very common in everyday Danish.

Because modern spoken Danish often prefers these two-word expressions.

There are also more formal or written-style single-word demonstratives:

• disse = these
• de = those / those ones in some formal contexts

But in normal conversation, learners will hear de her and de der much more often.

So:

• de her pensler sounds natural and everyday
• disse pensler sounds more formal or written

Both are plural noun forms.

• en pensel → pensler
• en rulle → ruller

A very common way to form the plural in Danish is to add -er, although not all nouns follow the same pattern.

So here, because the sentence is talking about more than one brush and more than one roller, the plural forms are used.

Because lille is not the plural form.

The adjective small behaves like this:

• singular, indefinite: lille
• plural: små
• often also in definite contexts: små

Examples:

• en lille pensel = a small brush
• små pensler = small brushes
• de små pensler = the small brushes

So De her pensler er små is correct because pensler is plural.

Because god has an irregular comparative.

Its forms are:

• god = good
• bedre = better
• bedst = best

So:

• rullerne er gode = the rollers are good
• rullerne er bedre = the rollers are better

This is like English good → better → best, not gooder.

Bedre til means better for, better suited to, or better to use for.

So:

• bedre til den store væg means the rollers are more suitable for the big wall

This use of til is very common when talking about purpose or suitability.

Compare:

• god til børn = good with children / good for children
• god til arbejdet = good for the job
• bedre til den store væg = better for the big wall

Because Danish normally uses a special structure when a definite noun has an adjective before it:

• den + adjective + noun

So:

• væggen = the wall
• den store væg = the big wall

When there is an adjective like store, Danish usually does not use the suffixed definite form on the noun itself.

So you get:

• væggen = the wall
• den store væg = the big wall

Not den store væggen.

Because adjectives usually take -e in definite noun phrases.

Here the noun phrase is definite:

• den store væg = the big wall

So the pattern is:

• en stor væg = a big wall
• den store væg = the big wall

This -e is very common after den, det, and de when an adjective comes before the noun.

Because væg is a common-gender noun, and common-gender nouns use den.

In Danish:

• den = for en-words (common gender)
• det = for et-words (neuter)

Since it is:

• en væg

it must be:

• den store væg

If it were a neuter noun, you would use det instead.

No, the word order here is normal.

The sentence has two coordinated clauses:

• De her pensler er små
• og de der ruller er bedre til den store væg

After og, Danish usually keeps normal main-clause word order:

• subject + verb + rest

So:

• de der ruller = subject
• er = verb

There is no inversion here.

Yes, Danish has other ways to express the same idea.

For example, you may also see postposed her/der:

• penslerne her = these brushes
• rullerne der = those rollers

That structure is also common.

But de her pensler and de der ruller are extremely natural and very common in everyday Danish, so they are well worth learning first.