1. In reality, I didn't pass the exam.
2. The fact is that I didn't pass the exam.
1 is grammatically correct, but number 2 is more common and sounds more natural.
You can use this to bring conversation back to the *facts*, if you think that you or your partner have been talking too much about ideas or dreams.
I do not think there are any other ways to say exactly this in English.
Also:
In English you "take an exam". When you take an exam you may "pass" or "fail". For example:
"I've taken the exam three times, but I failed each time"
"I took the exam and passed"
"I've taken the exam, but I will only know next week if I passed or failed"
So you could use 1. Past Simple tense or 2. Present Perfect tense
1) The fact is that I didn't pass the exam
2) The fact is that I haven't passed the exam
1 means that you took the exam but failed. 2 means that you have never taken the exam, perhaps you hope to take it in the future.