אני סומכת עליה, כי היא תמיד אומרת לי אם יש בעיה.

Because סומכת is the feminine singular present-tense form of the verb לסמוך.

In אני סומכת עליה, the speaker is female.
If the speaker were male, it would be אני סומך עליה.

The same thing happens later in היא תמיד אומרת לי: אומרת is feminine singular because היא means she.

In Hebrew, the common verb pattern for trusting someone is לסמוך על מישהו / מישהי.

So Hebrew says, literally, something closer to rely on someone or count on someone, even when the natural English translation is trust someone.

That means the preposition על is required:

• אני סומכת עליה = I trust her
• not אני סומכת אותה

This is just the normal Hebrew combination to memorize: לסמוך על.

עליה here means on her.

It is made from:

• על = on
• plus a pronoun ending meaning her

Hebrew very often attaches pronouns directly to prepositions:

• עלי = on me
• עליך / עלייך = on you
• עליו = on him
• עליה = on her
• עלינו = on us

So in this sentence, סומכת עליה is literally trusts on her / relies on her, but the natural English meaning is trusts her.

Here it is pronounced aleha and means on her.

That matters because the same unpointed spelling עליה can also represent the word aliyah in other contexts. In this sentence, though, after סומכת, it clearly means on her.

Sometimes yes, but in the present tense, Hebrew often keeps the subject pronoun because the verb form does not clearly show person.

For example, סומכת can mean:

• I trust (female speaker)
• you trust (feminine singular)
• she trusts

So אני helps make it clear that the meaning is I trust.

In past and future tense, subject pronouns are more often omitted because the verb usually shows person more clearly.

They are two different conjunctions:

• כי = because
• אם = if

So the sentence structure is:

• אני סומכת עליה = I trust her
• כי = because
• היא תמיד אומרת לי אם יש בעיה = she always tells me if there is a problem

A learner should not confuse them:

• כי gives a reason
• אם introduces a condition or possibility

Because לי means to me, and with לומר the person receiving the message is usually marked with ל־.

So:

• היא אומרת לי = she says to me / she tells me
• אמרתי לו = I said to him
• הם אמרו לנו = they said to us

A direct object like אותי would not work here.

In this sentence, the actual content of what she tells me is the clause אם יש בעיה.

Literally, it is closer to says to me, but in natural English this sentence is usually translated as tells me.

So:

• היא תמיד אומרת לי אם יש בעיה
  can be understood literally as
• she always says to me if there is a problem

but the natural English meaning is:

• she always tells me if there is a problem
• or she always lets me know if there’s a problem

יש is the standard Hebrew word for there is / there are.

So:

• יש בעיה = there is a problem
• יש זמן = there is time
• יש אנשים = there are people

Hebrew does not need a separate word like English there in this kind of sentence.
So אם יש בעיה is simply if there is a problem.

Because בעיה here means a problem, not the problem.

So:

• יש בעיה = there is a problem
• הבעיה = the problem

In this sentence, the idea is general and indefinite: if there is a problem.

Because that is a very natural place for an adverb like תמיד in Hebrew.

So:

• היא תמיד אומרת לי = she always tells me

Hebrew word order is somewhat flexible, but placing תמיד before the verb is very common and neutral.

Other orders may be possible in some contexts, but היא תמיד אומרת לי sounds very natural.

Yes, but the nuance changes.

• אם יש בעיה = if there is a problem
• כשיש בעיה = when there is a problem or whenever there is a problem

The original sentence emphasizes that she tells me in case a problem exists.
Using כשיש would sound a little more like whenever a problem comes up.

Both can make sense, but they are not exactly identical.

If the speaker were male:

• אני סומך עליה, כי היא תמיד אומרת לי אם יש בעיה.

If the trusted person were male:

• אני סומכת עליו, כי הוא תמיד אומר לי אם יש בעיה.

If both were male:

• אני סומך עליו, כי הוא תמיד אומר לי אם יש בעיה.

So you need to watch two different things:

• the form of the verb, which agrees with the subject
• the pronoun attached to the preposition, such as עליו or עליה