mosi youken ga owattara, eki mae no kafe de aimasyou.

もし adds an if feeling and signals a condition: if your business is finished...

It is often used with condition forms like たら, ば, なら, and と. In this sentence, it pairs with 終わったら.

It is not strictly necessary. You could say:

用件が終わったら、駅前のカフェで会いましょう。

and it would still be natural. Adding もし just makes the conditional relationship a little clearer or more explicit.

用件 means something like:

• business
• errand
• matter to take care of
• what you need to do

It is a somewhat formal or neutral word. In everyday conversation, depending on context, people might also use words like:

• 用事 = errand, something to do
• 仕事 = work

So 用件が終わったら means when/if you finish what you need to do.

Here, が marks 用件 as the thing that is finished.

With verbs like 終わる, the thing that ends or finishes is often marked with が:

• 会議が終わる = the meeting ends
• 授業が終わる = class ends
• 用件が終わる = the business/errand is finished

Using は would change the nuance and sound less natural here unless you were contrasting it with something else.

So 用件が終わったら is the normal way to say if/when your errand is finished.

This is a very common point of confusion.

In Japanese, たら attaches to the past short form of a verb, but that does not necessarily mean the whole sentence is talking about the past.

So:

• 終わる = to finish
• 終わった = finished
• 終わったら = if/when it has finished, after it finishes

In this pattern, the past form + ら creates a condition: when/if X happens.

So 終わったら does not mean the whole event is already in the past. It means once it is finished.

It can mean either if or when, depending on context.

In this sentence, the natural interpretation is often closer to:

• when you’re done
• once you finish

because the speaker seems to expect that the other person’s business probably will end.

But grammatically, たら can cover both if and when. Japanese often leaves that distinction to context.

駅前 means in front of the station or the area around the front of the station.

It is a very common compound noun:

• 駅 = station
• 前 = front
• 駅前 = station-front area / in front of the station

It is similar to 駅の前, but not always identical in nuance:

• 駅の前 sounds more literally like right in front of the station
• 駅前 often refers more broadly to the area around the station front

So 駅前のカフェ means the café near/in front of the station.

The の connects nouns.

Here, 駅前 describes カフェ:

• 駅前 = station-front area
• カフェ = café
• 駅前のカフェ = the café near/in front of the station

This is a very common noun-linking pattern in Japanese:

• 日本の車 = Japanese car / car of Japan
• 学校の先生 = school teacher
• 駅前のカフェ = café by the station

Here, で marks the place where the action happens.

Since 会う is the action to meet, the café is the location of that meeting:

• カフェで会う = meet at a café

A helpful way to think about it:

• で = where an action takes place
• に = destination, existence, or a specific target in many other patterns

With 会う, Japanese commonly uses the place with で when saying where the meeting happens.

会いましょう is the polite volitional form of 会う.

• 会う = to meet
• 会いましょう = let’s meet / shall we meet

It is used to make a suggestion or invitation.

So the sentence ends with a polite suggestion: let’s meet at the café by the station.

It is softer and more cooperative than a plain command.

Because the speaker is proposing a plan, not just stating a fact.

Compare:

• 会います = I/you/we will meet
• 会いましょう = let’s meet

In this sentence, the speaker is suggesting what both people should do after the errand is finished, so 会いましょう is the natural choice.

Japanese often leaves out subjects and pronouns when they are understood from context.

In this sentence:

• 用件が終わったら probably refers to your business/errand being finished
• 会いましょう means let’s meet, so it includes you and I / we

A natural English translation needs to add those pronouns, but Japanese usually does not need them if the situation is clear.

Yes, very often you could.

For example:

もし用事が終わったら、駅前のカフェで会いましょう。

This would sound a bit more everyday and casual.
用件 is a little more formal or businesslike than 用事.

So the choice depends on tone and context:

• 用件 = somewhat formal, matter/business
• 用事 = everyday errand, something to do

Yes. The comma helps separate the condition from the main action:

• もし用件が終わったら、 = if/when your business is finished,
• 駅前のカフェで会いましょう。 = let’s meet at the café by the station.

It makes the sentence easier to read and gives a natural pause. In writing, it is common and helpful here, though punctuation in Japanese can be somewhat flexible.