Manchmal fällt es mir leicht, geduldig zu bleiben, manchmal fällt es mir schwer, aber meine Freundin erinnert mich an die Fortschritte.

The pattern es fällt mir leicht/schwer, etwas zu tun literally means “it falls to me easily/hard to do something,” but idiomatically it means “it is easy/difficult for me to do something.”

• es fällt mir leicht, … = it is easy for me to …
• es fällt mir schwer, … = it is hard/difficult for me to …

You can also say es ist leicht für mich, geduldig zu bleiben, but:

• es fällt mir leicht/schwer sounds more natural and idiomatic in German, especially for talking about how something feels to you personally.
• es ist leicht für mich is correct but often sounds a bit more static or neutral.

So in everyday speech, Germans strongly prefer es fällt mir leicht/schwer in this context.

You cannot leave out the es here. In es fällt mir leicht, …, the es is a dummy subject (also called an “anticipatory es”). The real content is in the following zu + infinitive clause:

• Es (dummy subject)
• fällt (verb)
• mir (dative = to me)
• leicht (adjective = easy)
• geduldig zu bleiben (the actual thing that is easy)

German grammar requires a subject, so es fills that slot while the zu bleiben clause provides the content.

✅ Correct: Manchmal fällt es mir leicht, geduldig zu bleiben.
❌ Incorrect: Manchmal fällt mir leicht, geduldig zu bleiben. (missing subject)

With fallen in this expression, the person who experiences the ease/difficulty is in the dative case:

• jemandem fällt etwas leicht/schwer
  = something is easy/hard for someone.

So:

• es = (dummy) subject
• mir = indirect object in the dative (“to me”)

Compare:

• Es fällt mir leicht. = It is easy for me.
• Es fällt ihm schwer. = It is hard for him.
• Es fällt uns leicht. = It is easy for us.

Using mich here would be ungrammatical, because mich is accusative and this verb construction requires dative for the experiencer.

In German, after certain adjectives and expressions (like es fällt mir leicht/schwer), an action is expressed with zu + infinitive:

• es fällt mir leicht, geduldig zu bleiben
• es ist wichtig, geduldig zu bleiben
• ich versuche, geduldig zu bleiben

So geduldig zu bleiben = “to remain patient.” Without zu, it would be incomplete here. The pattern is:

es fällt mir leicht/schwer, + zu + infinitive

You would use bare infinitives (without zu) with modal verbs or a few special verbs:

• ich will geduldig bleiben (want to)
• ich kann geduldig bleiben (can)
• ich muss geduldig bleiben (must)

But with es fällt mir leicht, you need zu.

Both are grammatically possible, but they do not mean the same:

• geduldig zu bleiben = to stay/remain patient (focus on continuing to be patient over time)
• geduldig zu sein = to be patient (more general state, not emphasizing continuity)

In your sentence, the idea is that patience has to be maintained over a period, so geduldig zu bleiben (remain patient) is more precise and natural.

If you said:

• Manchmal fällt es mir leicht, geduldig zu sein …

it would sound a bit more general and less about keeping patience over time.

German main clauses follow the verb-second rule (V2): the finite verb must be the second element.

In Manchmal fällt es mir leicht …:

1. Manchmal (first element)
2. fällt (finite verb, second position)
3. es mir leicht … (rest of the clause)

You can move elements around as long as the verb stays in second position:

• Es fällt mir manchmal leicht, geduldig zu bleiben.
• Mir fällt es manchmal leicht, geduldig zu bleiben.

All of these are correct. The different orders just change which part is emphasized:

• Manchmal fällt es mir leicht … = emphasizes “sometimes”
• Mir fällt es manchmal leicht … = slightly stronger focus on me
• Es fällt mir manchmal leicht … = more neutral/flexible word order

The comma before geduldig zu bleiben is mandatory in standard German, because you have an infinitive clause with zu that depends on an expression (es fällt mir leicht):

• …, fällt es mir leicht, geduldig zu bleiben, …

The general rule:
You must use a comma before a zu + infinitive clause when it depends on a specific word or expression like:

• es fällt mir leicht/schwer, …
• es ist wichtig, …
• er versucht, …

So here the comma is not optional. Leaving it out would be considered a punctuation mistake in standard written German.

All three can translate as “difficult/hard”, but there are nuances:

• schwer
  
  • Very common with es fällt mir schwer, …
  • Sounds natural and idiomatic in this fixed expression.
• schwierig
  
  • Often used for tasks, problems, situations:
    
    • eine schwierige Aufgabe
  • You could say es ist schwierig für mich, geduldig zu bleiben, but
    
    • es fällt mir schwer is more idiomatic and more about the personal effort involved.
• hart
  
  • Often emotionally or physically hard, sometimes harsher in tone:
    
    • Es ist hart für mich, das zu akzeptieren.

In this exact pattern, leicht/schwer fallen is the standard collocation, so schwer is the natural choice.

The verb erinnern has two common patterns:

1. jemanden an etwas erinnern (active, transitive)

   • meine Freundin erinnert mich an die Fortschritte
   • meine Freundin = subject (nominative)
   • mich = direct object (accusative, the person being reminded)
   • an die Fortschritte = prepositional object (accusative after an)
   • Meaning: “My girlfriend reminds me of the progress.”

2. sich an etwas erinnern (reflexive, “to remember”)

   • ich erinnere mich an die Fortschritte
   • Meaning: “I remember the progress.”

So in your sentence, it’s the non-reflexive pattern: someone else is actively reminding the speaker.

With jemanden an etwas erinnern, the preposition must be an + accusative:

• jemanden an etwas erinnern = to remind someone of something

So:

• meine Freundin erinnert mich an die Fortschritte ✅
• meine Freundin erinnert mich über die Fortschritte ❌ (wrong with erinnern)
• meine Freundin erinnert mich von den Fortschritten ❌

Note:
You can use other prepositions with other verbs:

• über die Fortschritte sprechen = speak about the progress
• von den Fortschritten erzählen = tell (someone) about the progress

But specifically with erinnern, it is immer: an + Akkusativ.

Both are possible, but they have different nuances:

• der Fortschritt (singular)

  • The general concept of progress, or a single step of progress.
  • Sie macht großen Fortschritt. (less common; sounds more like “one big step.”)

• die Fortschritte (plural)

  • Multiple improvements or multiple “steps forward.”
  • Very common when talking about ongoing, repeated small advances.

In meine Freundin erinnert mich an die Fortschritte, the plural implies:

• There have been several small or continuous improvements, and she reminds me of all those little steps.

That fits well with motivation and encouragement contexts.

meine Freundin can mean either:

1. my girlfriend (romantic partner), or
2. my (female) friend (non-romantic)

Context decides. In everyday conversation, if an adult says meine Freundin without extra context, it is often understood as “my girlfriend.” To avoid ambiguity:

• To stress non-romantic friendship, people might say:
  
  • eine Freundin von mir = a (female) friend of mine
• To stress romantic relationship, people sometimes add:
  
  • meine feste Freundin = my steady girlfriend

In your sentence, without extra context, it will usually be read as “my girlfriend.”

In German, aber introduces a new main clause, so a comma before it is required:

• …, manchmal fällt es mir schwer, aber meine Freundin erinnert mich an die Fortschritte.

You normally don’t use semicolons in this spot in modern German. A semicolon is possible in very formal or stylistic writing, but the default and most natural punctuation is:

• …, aber …

So: comma before aber, no semicolon needed.