החברה שלי שרה יפה, אבל היא לא אוהבת לשיר לבד מול הרבה אנשים.

In Hebrew, possession with שלי often uses the definite article ה־:

• החברה שלי = my girlfriend / my female friend
• הספר שלי = my book
• האוטו שלי = my car

So even though English does not say the my girlfriend, Hebrew commonly does say the equivalent of the girlfriend of mine.

Also, חברה שלי without ה־ is possible in some contexts, but it can sound more like a friend of mine or be less specifically definite.

It can mean all three, depending on context:

• חברה = female friend
• חברה שלי = often my girlfriend or my female friend
• חברה can also mean company

Here, the rest of the sentence talks about singing and not liking to sing alone in front of many people, so company does not fit. Context tells you it means a woman, not a business.

Here it is a verb, not a name.

Hebrew does not use capital letters, so שרה could be:

• Sarah / Sara the name
• sings / is singing
• sang

You tell from context. In this sentence, החברה שלי שרה יפה clearly means my girlfriend/female friend sings beautifully, so שרה is the verb.

Because Hebrew sometimes uses the same form for both, you often need context.

• היא שרה can mean she sings / is singing
• היא שרה can also mean she sang

Context decides:

• אתמול היא שרה = Yesterday she sang
• היא שרה כל יום = She sings every day

In your sentence, the whole statement is a general description of her habits, and the next clause is clearly present tense: היא לא אוהבת לשיר = she doesn’t like to sing. So שרה is understood as sings.

Because the subject is feminine: החברה שלי and later היא.

In Hebrew, present-tense verb forms agree with gender and number:

• masculine singular: שר, אוהב
• feminine singular: שרה, אוהבת

So for a woman, Hebrew uses:

• היא שרה
• היא אוהבת

If the subject were male, it would be:

• החבר שלי שר יפה, אבל הוא לא אוהב לשיר...

Hebrew often uses an adjective where English uses an -ly adverb.

So:

• יפה literally means beautiful / יפה
• but after a verb it can mean beautifully / nicely

That is why:

• היא שרה יפה = she sings beautifully

A useful thing to notice: in this adverb-like use, יפה does not change for gender here. You still say:

• הוא שר יפה
• היא שרה יפה

לשיר is the infinitive, meaning to sing.

After verbs like like, want, can, start, Hebrew usually uses ל־ + infinitive:

• אוהבת לשיר = likes to sing
• רוצה לאכול = wants to eat
• יודעת לקרוא = knows how to read

So לשיר is the normal Hebrew way to say to sing after אוהבת.

It could sometimes be omitted if the context is very clear, but היא is very natural here.

One important reason is that in the present tense, Hebrew verbs do not show person very clearly the way English does. For example, אוהבת tells you feminine singular, but not by itself whether the subject is she, you (feminine), etc. So Hebrew often includes the subject pronoun for clarity:

• אבל היא לא אוהבת לשיר... = clear and natural

So using היא here is normal and helpful.

לבד means alone, by oneself, or on one’s own.

In this sentence:

• לשיר לבד = to sing alone

So the idea is that she does not like singing when she is by herself in front of many people.

Yes. מול basically means facing, opposite, or in front of.

With people or an audience, it often means:

• in front of
• before

So:

• לשיר מול הרבה אנשים = to sing in front of many people

Hebrew could also say לפני הרבה אנשים, which also means in front of / before many people. In everyday speech, מול is very common and natural.

Both are correct, but they sound a little different.

• הרבה אנשים = many people — very common in everyday speech
• אנשים רבים = many people — a bit more formal or written

So הרבה אנשים is the more conversational choice here.

Also notice that הרבה stays the same form here; it does not change to match the noun.