"I need to know the truth."
Translation:Mi bezonas scii la veron.
I know it's old but it might help someone.
Scii means "have knowledge of" (a fact, an information, an opinion etc.)
Example: I need to have knowledge of the truth.
Koni refers to "being acquainted with" (someone, an animal, a place etc.)
Example: Sofia? Yes, I am acquainted with her.
Just say "est-see-ee", without the first E in est.
Phonetic breakdown (this always helps me):
S: S. This is where the S in the "est" comes from.
C: Ts. This is where the "t" in est and "s" in see come from.
I: Ee. This is where the two ees come from, the - is a slight pause.
Stsee-ee. It's difficult, I know.