why "believe" is not accepted? To believe = credere, to think = pensare

He is definitely not talking about the clitics.

When I would like to say - it's easier yhen i thought ---- can it be just --- E piu facile di credevo ??

'It is easier than what I was thinking' - would that be correct as well?

What about "cue che" instead of "quello che"? Would it be correct?

credevo = i believed why i thought

'It is easier than I thought it would be' - and I thought it worth spelling out!

why is "it is easier than i would believe" incorrect?

why did they not use "pensavo"?

In the exercise going from English to Italian, the "correct" answer is given as È più facile di quanto pensassi - in subjunctive tense, before we get to the subjunctive module. And there is no che in that sentence. One user commented that Duo accepted di quanto ho pensato.

Obviously, an error of some sort is happening with this particular sentence. Very confusing.

Pronunciation of quello seems to vary a bit:
https://forvo.com/word/quello/#it
One Italian uses a kind of "a" sound: "Quayl-lo" (like the audio female voice here), while the other uses a short "e": "Quehl-lo"

I thought credere means - to believe

Would DL ever look at my answer and mark it correct, please

why can't translate it as: It is easier than I believed

No, non è vero...!