Tratamentul preventiv depinde de talie.

Tratamentul means the treatment. Romanian usually puts the definite article at the end of the noun instead of using a separate word like English the.

• tratament = treatment
• tratamentul = the treatment

So Tratamentul preventiv means the preventive treatment.

In Romanian, adjectives often come after the noun they describe.

• tratamentul preventiv = the preventive treatment

This is one of the most common adjective patterns in Romanian.
Sometimes adjectives can come before the noun, but after the noun is the neutral, standard order in many cases.

Preventiv means preventive or for prevention.

It is related to:

• a preveni = to prevent
• prevenție = prevention
• preventiv = preventive

So tratamentul preventiv is treatment meant to prevent something, not necessarily to cure something already present.

A depinde de means to depend on.

The verb a depinde normally requires the preposition de, just as English depend normally requires on.

• depinde de vreme = depends on the weather
• depinde de preț = depends on the price
• depinde de talie = depends on size/build

So you should learn it as a fixed pattern:

• a depinde de ceva = to depend on something

Depinde is the 3rd person singular present form of a depinde.

The subject here is tratamentul preventiv, which is singular, so the verb must also be singular:

• tratamentul ... depinde = the treatment depends

Some useful present-tense forms:

• eu depind = I depend
• tu depinzi = you depend
• el/ea depinde = he/she/it depends

Talie can have more than one meaning depending on context. Common meanings include:

• waist
• stature / build / size

In a sentence like Tratamentul preventiv depinde de talie, it usually means something like body size, build, or stature, not literally waist in the clothing sense.

So the idea is that the preventive treatment depends on the person’s or animal’s physical size/build.

Yes. Talie is feminine.

You can see this in forms like:

• o talie = a size / a stature
• talia = the size / the stature / the waist

It is also a noun ending in -ie, which is very often feminine in Romanian.

Romanian adjectives change form to agree with the noun in gender and number, but some adjective forms look the same in certain contexts.

Here:

• tratamentul is masculine singular
• so the adjective is also masculine singular: preventiv

Compare:

• tratament preventiv = preventive treatment
• măsură preventivă = preventive measure

Notice the feminine singular form:

• preventivă

A rough pronunciation guide is:

trah-tah-MEN-tool preh-ven-TEEV deh-PIN-deh deh TAH-lee-eh

A few details:

• tr in tratamentul is pronounced clearly
• ă is a short central vowel, somewhat like the vowel in about
• depinde has stress on -pin-
• talie is pronounced in three syllables: ta-li-e

Yes. That would simply mean The treatment depends on size/build.

Adding preventiv makes the meaning more specific:

• Tratamentul depinde de talie = The treatment depends on size/build.
• Tratamentul preventiv depinde de talie = The preventive treatment depends on size/build.

So preventiv narrows down what kind of treatment is being discussed.

The given word order is the most natural neutral order:

• Tratamentul preventiv depinde de talie.

Romanian word order is fairly flexible, but changes in order usually affect emphasis. For example, you might move words around in special contexts, but the standard version for a learner is the original one.

So this is the safest pattern to remember:

• subject + adjective + verb + prepositional phrase

Word-for-word, maybe, but that is not how English normally says it. In Romanian, depinde de is a fixed structure, so de talie is just the object of that preposition.

A more natural English rendering is:

• depends on size
• depends on build
• depends on stature

So it is better not to translate de literally every time. Learn the whole phrase:

• a depinde de = to depend on