Magkunwari kang masaya.

Yes. In this sentence, magkunwari is being used as an imperative, so it gives a command or instruction.

A useful pattern to remember is:

• Magbasa ka. = Read.
• Maghintay ka. = Wait.
• Magkunwari ka... = Pretend...

With many mag- verbs, the same basic form can serve as both the dictionary form and the command form.

That is normal in Filipino. The short pronoun ka usually comes after the predicate or verb, not before it.

So the natural order is:

• Magkunwari ka...

not

• Ka magkunwari...

This often feels reversed to English speakers, because English usually puts the subject first, but Filipino commonly puts the verb or predicate first.

Kang is ka plus the linker -ng.

When ka is followed smoothly by another word or phrase, it often becomes kang:

• Magkunwari ka. = Pretend.
• Magkunwari kang masaya. = Pretend happy / Pretend that you are happy.

So here, kang connects ka to what follows, which is masaya.

Mag- is a very common verbal prefix in Filipino. It often marks an actor-focused verb.

In magkunwari, it turns kunwari into a verb meaning to pretend / to act as if.

For a beginner, the simplest way to think about it is:

• mag- helps form the verb
• magkunwari = pretend

You do not need to translate mag- by itself every time, but it is useful to recognize it because many everyday verbs use it.

Because Filipino often does not need a separate verb like English to be in this kind of structure.

English says:

• pretend you are happy

But Filipino can simply say:

• magkunwari kang masaya

The idea of being happy is understood from the adjective masaya and the whole sentence structure. This is very common in Filipino.

Masaya is an adjective, and it tells you the state or quality that the person is supposed to pretend to have.

So after magkunwari, you can put different kinds of things:

• Magkunwari kang masaya. = pretend happy
• Magkunwari kang pagod. = pretend tired
• Magkunwari kang doktor. = pretend to be a doctor

So masaya is the description of what kind of appearance or state is being faked.

Normally, no. Magkunwari ka masaya sounds incomplete or awkward because it is missing the linker.

The natural version is:

• Magkunwari kang masaya.

Another possible structure is:

• Magkunwari na masaya ka.

That version is also understandable, but it is structured a little differently and feels more like Pretend that you are happy.
The shorter, more compact pattern is Magkunwari kang masaya.

They are very close in meaning, and in many situations they can replace each other.

• Magkunwari kang masaya.
• Magpanggap kang masaya.

Both are natural.

A rough nuance is:

• magkunwari can feel a bit like act as if
• magpanggap can feel a bit more like pretend deliberately

But in everyday use, the difference is often small. A learner can safely understand them as near-synonyms.

You change the pronoun.

• Casual singular: Magkunwari kang masaya.
• Polite singular or plural: Magkunwari po kayong masaya.
• Casual plural: Magkunwari kayong masaya.

Notice the same pattern:

• ka → kang
• kayo → kayong

The linker shows up again before the following word.

By itself, yes—it is a fairly direct command.

If you want to soften it, you can add words such as muna, na lang, or use a less direct phrasing. For example:

• Magkunwari ka munang masaya. = Pretend to be happy for now.
• Magkunwari ka na lang na masaya. = Just pretend to be happy.
• Subukan mong magkunwaring masaya. = Try to act happy.

So the original sentence is natural, but it can sound strong depending on context and tone.