Mater dicit initium itineris facile esse, sed partem viae prope finem saepe gravem fieri.

Because after a verb of saying, thinking, knowing, and so on, Latin often uses indirect statement.

The pattern is:

• verb of saying/thinking
• accusative subject
• infinitive

So in this sentence:

• Mater dicit initium itineris facile esse
• Mater dicit partem viae ... gravem fieri

Literally, Latin says something like:

• Mother says the beginning of the journey to be easy
• Mother says part of the road to become heavy/difficult

In normal English we translate that more naturally as Mother says that the beginning of the journey is easy, but that part of the road near the end often becomes difficult.

In an indirect statement, the subject of the infinitive goes into the accusative case.

So:

• initium is the subject of esse
• partem is the subject of fieri

Even though they are the logical subjects of is easy and becomes difficult, they appear in the accusative because Latin is using the accusative-and-infinitive construction.

That is why you get:

• initium ... esse
• partem ... fieri

instead of nominatives like initium and pars functioning in a normal direct statement.

Because facile agrees with initium.

• initium is neuter singular
• so the adjective must also be neuter singular
• the neuter singular form of facilis is facile

So:

• initium facile esse = the beginning to be easy

If the noun were masculine or feminine singular, you would expect facilis instead.

Because gravem agrees with partem.

• partem is feminine singular accusative
• so the adjective must also be feminine singular accusative
• that form is gravem

So:

• partem ... gravem fieri = part of the road to become difficult/heavy/serious

This is the same agreement principle as with facile, just with a different gender.

Because Latin commonly uses the genitive with nouns like beginning, middle, end, part, and similar words.

So:

• initium itineris = the beginning of the journey

Here itineris depends on initium and tells you the beginning of what?

This is a very common pattern:

• initium pugnae = the beginning of the battle
• finis anni = the end of the year
• pars urbis = part of the city

For the same basic reason: pars often takes a genitive to show part of what.

So:

• partem viae = part of the road/path/way

This is often called a partitive genitive or simply a genitive dependent on pars.

So the structure is:

• partem = part
• viae = of the road

They are related, but not identical.

• iter usually means journey, trip, or march
• via usually means road, way, or path

So the sentence is nicely nuanced:

• initium itineris = the beginning of the journey
• partem viae = part of the road/path

In English, we might use journey and road somewhat loosely, but Latin often keeps the distinction clearer.

Because fieri means to become, to happen, or to be made depending on context.

Here it means to become:

• gravem fieri = to become difficult/heavy

So the contrast is:

• the beginning is easy
• a part near the end becomes difficult

If Latin had used gravem esse, it would mean to be difficult, not to become difficult. The use of fieri adds the idea of change.

Also, learners often notice that fio, fieri can function as the passive partner of facio, but here the simple meaning become is the important one.

Because prope takes the accusative case when it is used as a preposition.

So:

• prope finem = near the end

The noun finis has:

• nominative: finis
• accusative: finem

That is why Latin uses finem here.

Saepe is an adverb meaning often, and it modifies the verbal idea in the second clause.

So:

• partem viae prope finem saepe gravem fieri

means that it often happens that the part near the end becomes difficult.

In smoother English, we might say:

• the part of the road near the end is often difficult
• or often becomes difficult

Its exact placement can vary in Latin because word order is flexible, but here it clearly belongs with the second statement.

Yes. Sed means but, and it links two parallel indirect statements.

The full sense is:

• Mater dicit initium itineris facile esse
• sed (mater dicit) partem viae prope finem saepe gravem fieri

Latin often leaves out a repeated verb when it is easy to understand from context. So dicit is stated once, but it governs both infinitive clauses.

This kind of omission is very common and natural in Latin.

Because Latin word order is much freer than English word order. Latin relies more on endings than on position.

For example:

• initium is accusative because of its ending and form
• itineris is genitive because of its ending
• facile agrees with initium
• gravem agrees with partem

So Latin can arrange words for emphasis, balance, or style.

This sentence has a nice balance:

• initium itineris facile esse
• partem viae ... gravem fieri

The matching structure helps the reader hear the contrast between easy at the beginning and difficult near the end.

In many contexts, especially in later Latin, a quod clause can appear after verbs of saying or thinking. But in standard classical Latin, after a verb like dicit, the normal construction for indirect statement is the accusative with infinitive.

So classical prose strongly prefers:

• Mater dicit initium itineris facile esse

rather than something like:

• Mater dicit quod initium itineris facile est

A learner should treat the accusative-and-infinitive as the main expected pattern after verbs of saying.

Literally, gravis often means heavy, but very often it is used in a more figurative sense:

• heavy
• serious
• burdensome
• difficult

In this sentence, since it describes part of a journey or road, difficult or hard is the natural sense.

That is a good example of a Latin adjective keeping its core physical meaning while also extending into a more abstract one.