Non semper tantam patientiam habemus, quantam avia in rebus asperis ostendit.

It sets up a comparison of degree/amount:

• tantam = so great / so much
• quantam = as great / as much as

With patientiam, the whole pattern means as much patience as.

So the sentence is built like this:

• Non semper tantam patientiam habemus = We do not always have so much / that much patience
• quantam avia ... ostendit = as grandmother shows ...

This is a very common Latin correlative pattern.

Because the comparison is attached to a noun, patientiam.

• tam ... quam is usually used with adjectives or adverbs
  • for example, tam bonus quam... = as good as...
• tantus, -a, -um ... quantus, -a, -um is used when the idea is so great / as great, often with a noun
  • tanta patientia, quanta...
  • tantam patientiam, quantam...

So here Latin is not saying as patient; it is saying as much patience.

Because both words agree with patientiam.

• patientia is a feminine singular noun
• in this sentence it is in the accusative singular: patientiam

Therefore its modifiers must match it:

• tantam patientiam
• quantam [patientiam]

So the endings -am show agreement with patientiam.

It is understood, not repeated.

Latin often leaves out a repeated noun when it is obvious from context. So:

• quantam avia in rebus asperis ostendit

really means:

• quantam patientiam avia in rebus asperis ostendit

In English we often do something similar:

• We have as much patience as she shows instead of
• We have as much patience as the patience that she shows

Latin simply omits the repeated noun more freely.

Because it is the direct object of habemus.

• habemus = we have
• What do we have? patientiam

So patientiam must be accusative.

The same idea applies in the second clause too, where patientiam is understood as the object of ostendit:

• avia ... ostendit [patientiam] = grandmother shows patience

The sentence has two clauses, each with its own verb:

1. habemus

   • subject = we
   • Latin does not need to state nos, because -mus already tells you it is we

2. ostendit

   • subject = avia
   • avia is nominative singular, so it is the one doing the showing

So the structure is:

• we have
• grandmother shows

Avia is nominative because it is the subject of ostendit.

As for the/my/our:

Latin has no definite or indefinite article, so avia can mean:

• grandmother
• the grandmother
• sometimes, from context, even my grandmother or our grandmother

If Latin wants to be explicit, it can add a possessive such as mea avia or nostra avia. But often context is enough, so the possessive is omitted.

Literally it means something like:

• in harsh things
• in rough situations
• in difficult circumstances

A few details:

• res, rei is a very broad noun meaning thing, matter, affair, situation
• asper literally means rough, but very often figuratively means harsh, difficult, severe

So in rebus asperis is a natural Latin way to say in hard times or in difficult situations.

Because it follows in in the sense of in / during / amid a situation.

With in:

• in + accusative usually shows motion into
• in + ablative usually shows location or state/circumstance

Here there is no motion. The idea is in difficult circumstances, so Latin uses:

• in rebus asperis

This is a normal use of the ablative after in.

Because Latin often uses plural words like res to speak about circumstances, situations, affairs in a general way.

So in rebus asperis suggests:

• in difficult circumstances
• when things are hard
• in hard situations

A singular form would give a slightly different feel, often more like one specific matter or situation. The plural here is idiomatic and general.

It means not always.

That is important, because not always is different from never.

• Non semper tantam patientiam habemus = We do not always have that much patience
• It does not mean we never have it

So the sentence allows that sometimes we do show that level of patience, but not consistently.

Latin word order is flexible, and early position often gives emphasis.

By putting non semper first, the sentence immediately highlights the limitation:

• Not always do we have so much patience ...

That feels natural and emphatic. Latin could also say:

• Non semper habemus tantam patientiam...

That would still be correct. The given order just brings the contrast to the front.

No. Latin word order is much freer than English word order because case endings show grammatical roles.

For example, these are all broadly understandable Latin patterns:

• Non semper tantam patientiam habemus, quantam avia in rebus asperis ostendit.
• Non semper habemus tantam patientiam, quantam avia in rebus asperis ostendit.
• Quantam avia in rebus asperis ostendit, non semper tantam patientiam habemus.

The original order is elegant because it places:

• tantam patientiam early
• quantam later as the matching comparison

That pairing helps the reader hear the balance.

Both are present indicative active:

• habemus = we have
• ostendit = she shows

The present tense works well because the sentence is expressing a general truth or habitual observation, not one single event.

So the sense is something like:

• We do not always have as much patience as grandmother shows when circumstances are difficult.

Here it means shows.

This form is the present tense of ostendere.

That is worth noticing because some Latin verb forms can look ambiguous, but here ostendit is straightforwardly present. The sentence is comparing our patience with the patience grandmother shows in difficult circumstances.