टूथब्रश और टूथपेस्ट दाँतों के लिए हैं।

Because they are common English loanwords in Hindi. Hindi often uses borrowed words for modern everyday objects, especially products and technology, and writes them in Devanagari.

So:

• टूथब्रश = toothbrush
• टूथपेस्ट = toothpaste

This is very normal in modern Hindi. You may also hear more traditional words in some contexts, but these borrowed forms are widely understood and very common.

और means and.

It joins टूथब्रश and टूथपेस्ट into one combined subject:

• टूथब्रश और टूथपेस्ट = toothbrush and toothpaste

Because two things are being linked, the whole subject is plural.

Because के लिए requires the noun before it to be in the oblique case.

Here is the pattern:

• direct plural: दाँत = teeth
• oblique plural: दाँतों

So:

• दाँत = teeth
• दाँतों के लिए = for teeth

This is a very important Hindi pattern: when a noun is followed by a postposition such as के लिए, में, पर, से, etc., the noun often changes into its oblique form.

के लिए means for.

So:

• दाँतों के लिए = for teeth

A key difference from English is that Hindi uses postpositions, not prepositions. That means the equivalent of for comes after the noun phrase, not before it.

Compare:

• English: for teeth
• Hindi: दाँतों के लिए

Because के लिए is the normal fixed form used after nouns.

You should learn के लिए as a unit meaning for in sentences like this.

Examples:

• बच्चों के लिए = for children
• घर के लिए = for the house
• सीता के लिए = for Sita

So even though का/की/के can show possession in other situations, in के लिए you usually just use the standard expression as a whole.

Because the subject is plural.

The subject is:

• टूथब्रश और टूथपेस्ट = two things

When two nouns are joined by और, Hindi normally uses a plural verb. That is why the sentence ends with हैं.

Compare:

• टूथब्रश दाँतों के लिए है। = A toothbrush is for teeth.
• टूथब्रश और टूथपेस्ट दाँतों के लिए हैं। = Toothbrush and toothpaste are for teeth.

Because Hindi does not have articles like English a/an/the.

Very often, Hindi simply leaves that idea unspoken and the listener understands it from context.

So दाँतों can mean:

• teeth
• the teeth

depending on the situation.

That is completely normal in Hindi.

The basic order here is:

• Subject + phrase + verb

So:

• टूथब्रश और टूथपेस्ट = subject
• दाँतों के लिए = for teeth
• हैं = are

Hindi usually puts the main verb near the end of the sentence, so this order is very natural.

It is understandable and grammatically correct, but it does sound a little simple or textbook-like.

In everyday speech, many speakers might say something more specific, such as:

• टूथब्रश और टूथपेस्ट दाँत साफ़ करने के लिए होते हैं। = Toothbrush and toothpaste are for cleaning teeth.

Your sentence is still fine, especially for learning basic structure.

Yes, sometimes.

• ...के लिए हैं = are for
• ...के लिए होते हैं = are used for / are meant for in a more general or habitual sense

So:

• टूथब्रश और टूथपेस्ट दाँतों के लिए हैं।
  simple statement: Toothbrush and toothpaste are for teeth.

• टूथब्रश और टूथपेस्ट दाँत साफ़ करने के लिए होते हैं।
  more natural explanatory statement: Toothbrush and toothpaste are used for cleaning teeth.

In your sentence, हैं is perfectly fine.

A rough pronunciation is daã-tõ.

A few things to notice:

• ाँ shows nasalization on the vowel
• ों also gives a nasalized ending

So it is not just plain daato. English speakers often approximate it as daan-ton, but more accurately it has nasalized vowels rather than a strong full n sound in both places.

You do not need perfect nasalization immediately, but it is good to notice that it is there.

That mark is called the danda. It is the Hindi full stop.

So:

• । in Hindi works like
• . in English

You will see it at the end of many Hindi sentences.

In this sentence, you cannot really tell from the grammar, because the subject is a plural combination and the verb is just हैं.

In practice, many English loanwords in Hindi are often treated as masculine by default, especially in casual usage. For example, many speakers would naturally say things like:

• यह टूथब्रश अच्छा है।
• यह टूथपेस्ट अच्छा है।

But with loanwords, usage can vary somewhat by speaker and region. In your sentence, gender is not the main issue; the important thing is that the combined subject is plural, so the verb is हैं.