मेहमान का आगमन आज है।

It breaks down like this:

• मेहमान = guest
• का = of
• आगमन = arrival
• आज = today
• है = is

So the literal structure is basically guest-of arrival today is. Natural English turns that into The guest's arrival is today.

का is the genitive marker. It shows a relationship like of or English apostrophe-s.

So:

• मेहमान का आगमन = the guest's arrival
• literally, arrival of the guest

A very important point for learners: का/की/के agrees with the noun that comes after it, not with the person or thing doing the possessing.

Because आगमन is a masculine singular noun.

The usual pattern is:

• का for masculine singular
• की for feminine singular
• के for masculine plural, and also in some oblique situations

Since आगमन is masculine singular, Hindi uses का:

• मेहमान का आगमन

If the following noun were feminine, you would see की instead.

Because आगमन is a noun meaning arrival. This sentence is built like a noun-based statement, not a verb-based one.

So instead of saying:

• The guest arrives today

Hindi is saying something more like:

• The guest's arrival is today

This style is more formal and more written-sounding. In everyday conversation, speakers often prefer a verb, such as:

• मेहमान आज आएगा
• मेहमान आज आएंगे
• मेहमान आज आ रहा है

The best choice depends on number, politeness, and context.

It is grammatically correct, but it sounds formal and somewhat bookish.

You are more likely to see or hear this kind of wording in:

• announcements
• invitations
• formal writing
• religious or ceremonial language
• official contexts

In casual speech, many speakers would use a more direct sentence with a verb instead of आगमन.

Because Hindi usually puts the main verb, or the copula है, near the end of the clause.

So the order:

• मेहमान का आगमन आज है

is normal Hindi structure.

English tends to place is earlier, but Hindi often saves it for the end. That is one of the basic word-order differences between the two languages.

Yes, absolutely. That is also correct.

The difference is mainly emphasis:

• मेहमान का आगमन आज है puts the topic first, then tells you when
• आज मेहमान का आगमन है highlights today

Hindi word order is more flexible than English, especially when markers like का already show the relationship between words.

Not in this sentence.

मेहमान can refer to a guest without clearly showing gender here. Also, the form का is not telling you anything about the guest's gender, because का agrees with आगमन, not with मेहमान.

So from this sentence alone, you learn about the arrival, but not the guest's gender.

Yes, it could, but the tone changes.

• मेहमान का आगमन आज है sounds formal and polished
• मेहमान का आना आज है is understandable, but less elegant and still a bit stiff

In natural conversation, many speakers would usually switch to a verb-based sentence instead, such as:

• मेहमान आज आएगा
• मेहमान आज आएंगे
• मेहमान आज आ रहा है

So आगमन is correct, but it belongs more to formal style than everyday speech.