Avus dicit animum bonum veritatem amare.

A quick breakdown:

• avus = nominative singular, the subject of dicit
• dicit = he says, 3rd person singular present active
• animum = accusative singular of animus
• bonum = accusative singular masculine of bonus, modifying animum
• veritatem = accusative singular of veritas
• amare = present active infinitive, to love

So the main clause is:

• Avus dicit = Grandfather says

And then what he says is expressed by:

• animum bonum veritatem amare

That whole part is an indirect statement.

Because Latin is using the accusative-and-infinitive construction for indirect statement.

After verbs like:

• dicit = says
• putat = thinks
• audit = hears
• scit = knows

Latin often does not use a separate clause with that the way English does. Instead, it uses:

• an accusative subject
• plus an infinitive

So here:

• animum bonum is the subject of amare, but in the accusative because it is inside an indirect statement
• veritatem is the direct object of amare, also in the accusative because amare takes a direct object

That is why you see two accusatives in a row.

Because this is not a direct statement such as animus bonus veritatem amat.

Instead, it is an indirect statement after dicit. In this construction, Latin uses an infinitive:

• direct statement: animus bonus veritatem amat = the good mind loves truth
• indirect statement after dicit: dicit animum bonum veritatem amare = he says that the good mind loves truth

So amare is used because Latin is reporting what is said, not presenting it as a standalone finite clause.

Because in this kind of sentence Latin normally does not use a separate word meaning that.

English says:

• Grandfather says that ...

Latin often says:

• Grandfather says [accusative + infinitive]

So instead of a that-clause, Latin prefers:

• animum bonum veritatem amare

This is one of the most common patterns in Latin syntax.

Because adjectives must agree with the nouns they modify in:

• gender
• number
• case

Here:

• animum is masculine singular accusative
• bonum is masculine singular accusative

That matches perfectly.

But:

• veritatem is feminine singular accusative

If good were modifying veritatem, it would have to be bonam, not bonum.

So bonum can only go with animum here.

This is a very natural question, because both are accusative.

In the accusative-and-infinitive construction:

• one accusative is the subject of the infinitive
• another accusative can be the object of the infinitive

Here we understand:

• animum bonum = the one doing the loving
• veritatem = the thing being loved

Why?

1. Sense helps.
   It makes better sense for a good mind/spirit to love truth than for truth to love a good mind.

2. The adjective groups with animum.
   bonum clearly belongs to animum, so animum bonum forms a unit.

3. Word grouping helps.
   Latin often puts the accusative subject before the object in this kind of sentence, though this is not an absolute rule.

So grammar plus meaning together make the interpretation clear.

Yes, the word order is flexible.

Latin relies much more on endings than English does, so several orders are possible. For example:

• Avus dicit animum bonum veritatem amare
• Avus dicit bonum animum veritatem amare

Both can work.

A few useful points:

• animum bonum and bonum animum both mean good mind/spirit in the accusative
• bonus animus would be nominative, so that would not fit here
• placing amare at the end is very normal Latin style

So the order here is natural, but not the only possible one.

Animus is a broad word and can be tricky to translate with just one English word.

Depending on context, it can mean things like:

• mind
• spirit
• heart
• disposition
• courage
• character

So animum bonum is not necessarily a physical soul in a theological sense. It more often suggests a good spirit, good character, good heart, or good mind.

The best English wording depends on the context in which the sentence appears.

Because the phrase is not the subject of the main verb. It is inside an indirect statement, where the subject of the infinitive must be accusative.

Compare:

• bonus animus veritatem amat
  = a good mind loves truth
  Here bonus animus is nominative, the normal subject of a finite verb.

• avus dicit animum bonum veritatem amare
  = grandfather says that a good mind loves truth
  Here animum bonum is accusative because it is the subject of amare in indirect statement.

So the change from bonus animus to animum bonum is caused by syntax, not by a change in meaning.

The present infinitive amare shows action that is simultaneous with the main verb, relative to it.

So:

• dicit ... amare means he says that it loves / is loving

The loving is happening at the same time as the saying, at least from the speaker’s point of view.

This is part of the normal tense system of Latin indirect statement:

• present infinitive = same time
• perfect infinitive = earlier time
• future infinitive = later time

So amare is the expected form here.

Latin has no definite or indefinite articles.

So:

• avus can mean grandfather, a grandfather, or the grandfather
• animum bonum can mean a good mind, the good mind, or just good-mindedness depending on context
• veritatem can mean truth or the truth

The context tells you which English article, if any, sounds best.

That is why a Latin sentence can be slightly more open-ended than its English translation.