Ego sentio peregrinam illam benignam nobis magno auxilio fuisse, cum deversorium quaereremus.

Yes. The ending of sentio already tells you the subject is first person singular, so ego is not required.

When Latin includes ego, it usually adds some emphasis or contrast, such as:

• I think ...
• As for me, I think ...
• I myself think ...

So ego is there for stress, not because Latin needs it for grammar.

Because Latin commonly uses indirect statement, also called the accusative-and-infinitive construction.

After a verb like sentio, Latin often says:

• main verb of thinking/perceiving
• • accusative subject
• • infinitive

So here:

• sentio = I think / I realize
• peregrinam illam benignam = the woman being talked about, in the accusative
• fuisse = to have been / to have been

Together, sentio peregrinam illam benignam ... fuisse means I think that that kind stranger was ...

English uses that-clauses; Latin very often uses accusative + infinitive instead.

Because they all refer to the same woman, and in an indirect statement the subject of the infinitive goes into the accusative.

So:

• peregrinam = stranger / foreign woman
• illam = that
• benignam = kind

All three words agree in:

• gender: feminine
• number: singular
• case: accusative

They are all describing the understood subject of fuisse.

Peregrina can mean a foreigner, stranger, or traveler. The exact shade depends on context.

In this sentence, it most naturally means something like:

• that kind stranger
• that kind foreign woman
• that kind traveler

A native English speaker should be careful not to assume it means exactly the same thing as any one English word. It has a broader range.

Not exactly. This is a useful false-friend warning.

Latin benignus / benigna usually means:

• kind
• kindly
• gracious
• generous
• helpful

So benignam here means kind or kindly, not medically harmless or mild in the modern English sense of benign.

Illam is the demonstrative adjective/pronoun meaning that.

It agrees with peregrinam and helps identify the woman as that woman / that stranger.

Latin word order is much freer than English word order. So:

• peregrinam illam benignam
• illam peregrinam benignam
• peregrinam benignam illam

could all be possible, though not all would sound equally natural in a given context.

Here the order gives a nicely descriptive grouping: the stranger, that kind one. Latin often uses word order for style and emphasis rather than strict grammatical necessity.

This is a classic Latin pattern involving the dative.

• nobis = to us / for us
• magno auxilio = for great help or more naturally a great help

The whole expression alicui auxilio esse means to be a help to someone.

So:

• nobis ... auxilio fuisse = to have been a help to us

Because magno modifies auxilio, both are in the dative singular.

Yes, that is a very standard way to explain it.

There are two datives here:

1. nobis = dative of reference/advantage

   • to us, for us

2. magno auxilio = dative of purpose

   • for a great help
   • more idiomatically in English, a great help

So literally the Latin is something like:

• to us for great help

But natural English is:

• was a great help to us

This is one of the most common Latin idioms.

Because fuisse is the perfect infinitive of sum.

In indirect statement, the tense of the infinitive shows time relative to the main verb:

• esse = to be, contemporaneous with the main verb
• fuisse = to have been, earlier than the main verb

So sentio ... fuisse means something like:

• I realize that she was / has been ...

In smooth English, we usually just say was.

Here the idea is that the speaker now recognizes a past fact: that the woman was a great help at that earlier time.

Because this is the common cum + imperfect subjunctive construction used for a past circumstantial clause.

It gives the background situation:

• cum deversorium quaereremus = when / while we were looking for lodging

This kind of cum clause often does more than just state clock-time. It sets the scene or circumstances under which the main action happened.

So the subjunctive here is normal and expected.

Because the action in the cum clause is ongoing or in progress in the past:

• quaerebamus would mean we were looking
• quaereremus means the same basic time idea, but in the subjunctive because of cum

The imperfect is appropriate because the sentence describes a background activity:

• we were in the middle of looking for an inn
• during that time, the woman was a great help

So the imperfect gives the sense of ongoing past action.

Possibly in theory, because cum can have several meanings, including:

• when
• while
• since
• although

But in this sentence, the most natural reading is when or while:

• when we were looking for an inn
• while we were looking for lodging

That fits the context best: it tells us the situation in which she helped.

Because it is the direct object of quaereremus.

• quaerere = to look for, to seek
• What were we looking for? deversorium

So:

• deversorium = accusative singular neuter
• direct object of quaereremus

Deversorium means a place to stay, especially something like:

• inn
• lodging
• lodging place
• hostel / stopping place

In this sentence, inn or lodging works well.

Because Latin sentio has a wider range than English feel.

It can mean:

• perceive
• notice
• realize
• think
• judge
• feel

In this sentence, the sense is mental recognition, not physical sensation. So English usually prefers something like:

• I think
• I realize
• I can tell

That is why a more idiomatic translation uses a verb of thought or perception rather than literal bodily feeling.

It breaks down like this:

1. Ego sentio

   • main clause: I think / I realize

2. peregrinam illam benignam nobis magno auxilio fuisse

   • indirect statement: that that kind stranger was a great help to us

3. cum deversorium quaereremus

   • background cum clause: when/while we were looking for an inn

So the sentence is built as:

• main verb of thinking/perceiving
• • indirect statement
• • circumstantial cum clause

That is a very typical Latin sentence pattern.