Wij gaan ervan uit dat de trein op tijd komt.

Here ervan uitgaan means to assume, to suppose, or to proceed on the assumption that.

So Wij gaan ervan uit dat de trein op tijd komt means something like:

• We assume that the train will be on time
• We are assuming that the train will arrive on time

It is an idiomatic expression, so you should learn it as a set phrase.

Because Dutch often splits separable verbs or verb-like expressions in a main clause.

The basic expression is:

• ervan uitgaan

But in a normal main clause, the finite verb moves to the second position:

• Wij gaan ervan uit ...

So:

• gaan = the conjugated verb in second position
• uit = the separated particle
• ervan = part of the fixed expression

This is very common in Dutch. Compare:

• Ik sta op = I get up
• Wij gaan ervan uit = we assume

Ervan is made of:

• er
• van

The verb expression is related to uitgaan van, literally something like to proceed from. In this idiomatic meaning, Dutch uses ervan when the thing being assumed is expressed later by a clause.

So Dutch says:

• ervan uitgaan dat ...

You can think of ervan as a kind of placeholder that points forward to the dat-clause.

This is very common in Dutch with prepositions:

• Ik reken erop dat ... = I count on the fact that ...
• Hij droomt ervan dat ... = He dreams that ...
• Wij gaan ervan uit dat ... = We assume that ...

Because that is not natural Dutch.

A preposition like van does not normally connect directly to a dat-clause in this kind of structure. Dutch usually uses a pronominal adverb such as ervan, and then the clause comes after it.

So the natural pattern is:

• ervan uitgaan dat ...

not:

• uitgaan van dat ...

Not really. Even though gaan normally means to go, here it is part of the fixed expression ervan uitgaan.

So in this sentence, gaan does not describe movement. The whole expression means assume.

That is why you should not translate it word by word.

Both wij and we mean we.

The difference is mainly style and emphasis:

• we = more common in everyday speech
• wij = a bit more formal, careful, or emphatic

So these are both possible:

• Wij gaan ervan uit dat de trein op tijd komt.
• We gaan ervan uit dat de trein op tijd komt.

In normal conversation, we is very common.

Because dat introduces a subordinate clause, and in Dutch subordinate clauses the conjugated verb usually goes to the end.

So:

• main clause: Wij gaan ervan uit
• subordinate clause: dat de trein op tijd komt

This is a core Dutch word-order rule.

Compare:

• De trein komt op tijd. = main clause
• ... dat de trein op tijd komt. = subordinate clause

Because the subject is de trein, which is singular.

So the verb must also be singular:

• de trein komt = the train comes
• de treinen komen = the trains come

That is why komt is correct here.

Because Dutch often uses the present tense for future events, especially when they are expected, scheduled, or understood from context.

So:

• de trein komt op tijd can mean the train is arriving on time or the train will arrive on time

Dutch does not always need a separate future form like zal komen.

You could say:

• Wij gaan ervan uit dat de trein op tijd zal komen

but in many everyday situations, komt sounds more natural.

Op tijd means on time or punctually.

So:

• De trein komt op tijd = The train arrives on time

A useful comparison:

• op tijd = on time, not late
• te laat = too late / late

English learners sometimes compare on time and in time. Dutch op tijd usually matches on time best in a sentence like this.

Yes. Some common alternatives are:

• aannemen dat = to assume that
• veronderstellen dat = to suppose that
• denken dat = to think that

For example:

• Wij nemen aan dat de trein op tijd komt.
• Wij veronderstellen dat de trein op tijd komt.

But ervan uitgaan has a slightly special nuance: it often means to take something as your working assumption, the basis you are proceeding from unless there is evidence otherwise.

Usually no.

So the normal spelling is:

• Wij gaan ervan uit dat de trein op tijd komt.

In modern Dutch, a comma before dat is generally not used unless there is a special reason, such as clarity or a parenthetical interruption.

Because Dutch very often uses komen for vehicles and people arriving.

So these are natural:

• De trein komt om acht uur.
• De bus komt te laat.

You can say arriveren, but it is less everyday and often sounds more formal or less natural in many simple contexts.

So de trein op tijd komt is exactly the kind of Dutch a native speaker would normally say.

The form to learn is:

• ervan uitgaan

In a sentence, it gets split:

• Wij gaan ervan uit ...

With another verb form, you can also see the whole expression more clearly:

• We proberen ervan uit te gaan dat alles goed komt.

So a good way to remember it is:

• ervan uitgaan dat ... = to assume that ...