זה שאני עדיין לא בטוחה לא אומר שלא אתקבל.

Yes:

זה — this / the fact
שאני — that I am / that I
עדיין — still / yet
לא — not
בטוחה — sure, certain, confident (feminine)
לא אומר — does not mean
שלא — that not / that ... not
אתקבל — I will be accepted / I will get accepted

So the structure is basically:

זה שאני עדיין לא בטוחה — the fact that I’m still not sure
לא אומר — doesn’t mean
שלא אתקבל — that I won’t be accepted

This is a very common Hebrew pattern: זה ש...

It often means the fact that...

So:

זה שאני עדיין לא בטוחה
= the fact that I’m still not sure

Hebrew uses זה ש... very naturally in speech to turn a whole clause into the subject of the sentence.

A more formal version would be:

העובדה שאני עדיין לא בטוחה...
= the fact that I’m still not sure...

So זה here is not just the ordinary this. It helps create the meaning the fact that.

Both contain the prefix ש־, which usually means that.

So:

שאני = ש־ + אני = that I
שלא = ש־ + לא = that not / that ... not

Hebrew often attaches this ש־ directly to the next word, instead of writing it separately.

That is why you see one written unit:

שאני rather than ש אני
שלא rather than ש לא

Because the speaker is female.

בטוח = sure/certain (masculine)
בטוחה = sure/certain (feminine)

So this sentence is being said by a woman or girl.

If a man were speaking, it would be:

זה שאני עדיין לא בטוח לא אומר שלא אתקבל.

A useful thing to notice here is that אתקבל does not show gender, but בטוחה does. So the adjective is what tells you the speaker is female.

It can mean either one, depending on context.

Here, with בטוחה, the most natural English ideas are:

still not sure
or
not sure yet

So:

אני עדיין לא בטוחה
can be understood as
I’m still not sure
or
I’m not sure yet

Hebrew uses עדיין לא very commonly in exactly this kind of situation.

Because the grammatical subject is זה, and זה is treated as masculine singular.

So the sentence is structured as:

זה ... לא אומר ...
= this / the fact ... does not mean ...

That is why the verb is אומר.

Compare this with the more formal version:

העובדה שאני עדיין לא בטוחה לא אומרת שלא אתקבל.

Here the subject is העובדה, which is feminine, so the verb becomes אומרת.

So the difference is about grammatical agreement with the subject:

זה → אומר
העובדה → אומרת

Because each לא is negating a different part of the sentence.

The first לא negates the main verb:

לא אומר = does not mean

The second לא is inside the subordinate clause:

שלא אתקבל = that I will not be accepted

So the whole thing means:

It does not mean that I will not be accepted.

This is not a double negative in the sense of canceling itself out. English works the same way here:

It doesn’t mean that I won’t be accepted.

In fact, changing the second לא changes the meaning a lot:

לא אומר שאתקבל
= doesn’t mean that I will be accepted

But:

לא אומר שלא אתקבל
= doesn’t mean that I will not be accepted

אתקבל means I will be accepted or I will get accepted.

It comes from להתקבל, which means to be accepted, to get in, or sometimes to be admitted depending on context.

So:

להתקבל — to be accepted
אתקבל — I will be accepted

This is a very useful verb, especially for things like schools, jobs, programs, auditions, and applications.

Also, do not confuse it with:

אקבל — I will receive

That comes from לקבל.

So:

אקבל = I will receive
אתקבל = I will be accepted / get accepted

That extra ת is an important clue.

In Hebrew, להתקבל is the normal everyday verb for get accepted / be accepted in many situations.

For example:

היא התקבלה לאוניברסיטה
= She got accepted to the university

So even though English may use a passive like be accepted, Hebrew often uses להתקבל very naturally for this idea.

It is the standard verb you would expect in this sentence.

Yes, זה ש... is very natural and common in spoken Hebrew, and it also appears in informal writing.

A more formal version would be:

העובדה שאני עדיין לא בטוחה לא אומרת שלא אתקבל.

Both are correct, but they feel different:

זה שאני... — more conversational, everyday
העובדה שאני... — more formal, more written

So the original sentence sounds natural and idiomatic, especially in speech.