אני אופה עוגה גדולה, כי אני יודעת שהיא אוהבת עוגה מתוקה עם דבש.

Because the speaker is female. In Hebrew, אני means I for both men and women, so the speaker’s gender shows up in the verb form instead.

• אני יודע = a male speaker says I know
• אני יודעת = a female speaker says I know

Yes, it is feminine in this sentence, but you mostly know that from context.

In normal unpointed Hebrew spelling, אופה can represent:

• masculine אוֹפֶה
• feminine אוֹפָה

They are spelled the same without vowel marks. Here, the later word יודעת shows that the speaker is female, so אופה should be understood as feminine too.

Because its subject is היא = she. In Hebrew present tense, the verb agrees with the subject in gender and number.

• היא אוהבת = she likes/loves
• הוא אוהב = he likes/loves

So אוהבת is the correct feminine singular form.

שהיא is really two parts joined together:

• ש־ = that
• היא = she

So אני יודעת שהיא אוהבת... means I know that she likes/loves...

In modern Hebrew, ש־ is very often attached directly to the next word.

They do different jobs:

• כי = because
• ש־ = that

So the structure is:

• אני אופה עוגה גדולה = I am baking a big cake
• כי = because
• אני יודעת שהיא אוהבת... = I know that she likes/loves...

So the full logic is I am baking a big cake, because I know that she likes/loves...

Because in Hebrew, adjectives usually come after the noun they describe.

So:

• עוגה גדולה = a big cake
• עוגה מתוקה = a sweet cake

This is the normal Hebrew pattern: noun + adjective.

Because עוגה is a feminine singular noun, and the adjectives must agree with it.

So:

• עוגה is feminine singular
• גדולה is feminine singular
• מתוקה is feminine singular

The masculine singular forms would be:

• גדול = big
• מתוק = sweet

A very common rule in Hebrew is that adjectives match the noun in gender and number.

Because Hebrew has no indefinite article. There is no separate word for a or an.

So:

• עוגה can mean a cake
• העוגה means the cake

That is why עוגה גדולה naturally means a big cake.

Because they are indefinite or general here, not specific.

• עוגה גדולה = a big cake
• עם דבש = with honey

If you wanted the big cake, Hebrew would say:

• העוגה הגדולה

Notice that the ה־ appears on both the noun and the adjective in that kind of phrase.

And:

• עם הדבש would mean with the honey or with that specific honey

It can mean either, depending on context.

Hebrew present tense often covers both:

• I bake
• I am baking

So אני אופה עוגה גדולה could mean either I bake a big cake or I am baking a big cake, but in this sentence the natural English choice is usually I am baking a big cake.

Because Hebrew present-tense forms usually do not show person clearly by themselves. They often show gender and number, but not whether the subject is I, you, or she/he.

So:

• יודעת by itself could mean something like knowing or she knows or depend on context
• אני יודעת clearly means I know said by a female speaker

Likewise:

• אני אופה clearly tells you the subject is I

That is why subject pronouns are commonly used in Hebrew present-tense sentences.

Literally, it means with honey.

Depending on context, that could mean:

• the cake contains honey
• the cake is flavored with honey
• the cake is served with honey

Because דבש has no ה־, it sounds general: with honey, not with the specific honey.