Serva dominae bene servit, sed domina quoque servae saepe ignoscit.

Because serva is in the nominative singular, the case normally used for the subject.

In the first clause:

• serva = nominative singular, so the slave-woman is doing the action
• dominae = dative singular, so to/for the mistress
• servit = serves

So the grammar tells you that serva is the one serving.

In Latin, you often identify the subject by its case ending, not by its position in the sentence.

Because the Latin verb servire works differently from the English verb to serve.

Servire takes the dative case, not a direct object in the accusative. So:

• servit dominae = serves the mistress
• literally, something like is devoted/serviceable to the mistress

This is very common in Latin: some verbs take a different construction from the one English uses. So even though English has a direct object, Latin uses the dative here.

For the same basic reason: ignoscere commonly takes the dative of the person forgiven.

So in:

• domina quoque servae saepe ignoscit

the word servae means to the slave-woman or more naturally the slave-woman after forgives.

Latin is using the dative where English uses a direct object.

So both verbs in this sentence have the same important feature:

• servire
  • dative
• ignoscere
  • dative

You are right that -ae can be more than one case form. In the first declension, -ae can be:

• genitive singular = of the mistress
• dative singular = to/for the mistress
• also some plural forms in other contexts

So how do we know which one it is here?

We decide from the grammar of the verb and from the sense of the sentence.

Since servire takes a dative, dominae here must be dative, not genitive. Likewise, since ignoscere takes a dative of the person, servae is dative in the second clause.

This is a very normal part of reading Latin: the ending gives you possibilities, and the sentence tells you which one fits.

Quoque means also or too.

It is often placed after the word it especially emphasizes. So:

• domina quoque = the mistress also / the mistress too

That means the sentence is contrasting the two clauses:

• the slave serves the mistress well,
• but the mistress too often forgives the slave.

So quoque helps show that the second clause adds a matching idea.

Bene is an adverb, meaning well.

It modifies the verb servit:

• bene servit = serves well

This is the adverb corresponding to bonus, -a, -um (good). A beginner often notices that English uses different words too:

• good = adjective
• well = adverb

Latin does the same thing here:

• bonus / bona / bonum = good
• bene = well

Because Latin word order is much more flexible than English word order.

English depends heavily on position:

• The slave serves the mistress

If you rearrange that too much, the meaning changes or becomes unclear.

Latin depends much more on endings:

• serva tells you the subject
• dominae tells you the dative form
• servit tells you the verb

So Latin can move words around for style, emphasis, or rhythm without changing the basic meaning.

This sentence is quite natural Latin:

• Serva dominae bene servit
• sed domina quoque servae saepe ignoscit

The verbs come at the end of each clause, which is very common in Latin.

Yes. Serva means female slave or slave-woman.

Likewise:

• domina = mistress, lady of the house, or female master

The masculine forms would be:

• servus = male slave
• dominus = master, lord

So this sentence is specifically talking about two women.

A good way is to focus on the endings and on what kind of word each one is.

• serva ends in -a, a very common first-declension noun ending
• servit ends in -t, a very common verb ending meaning he/she/it ...s

So:

• serva = a noun, slave-woman
• servit = a verb, serves

Even though they look alike, they are from different dictionary forms:

• serva, -ae = slave-woman
• servio, servire = serve

This is a normal experience in Latin: words can resemble each other without being the same part of speech.

Saepe means often.

It modifies ignoscit:

• saepe ignoscit = often forgives

So the second clause does not just say that the mistress forgives the slave-woman; it says she does so frequently.

Its placement is flexible. Latin can put adverbs like saepe in different places, but here it fits naturally before the verb.

Yes, to a large extent.

Because the endings carry the main grammatical information, Latin could rearrange this sentence in several ways and still keep the same basic meaning. For example, forms like these would still be understandable:

• Dominae serva bene servit
• Serva bene dominae servit
• Domina servae quoque saepe ignoscit

The exact emphasis may change, but the core relationships remain the same because:

• serva and domina are nominative
• dominae and servae are dative
• servit and ignoscit are the verbs

So when reading Latin, it is important not to depend only on English-style word order.