ترجمه - دانمارکی-لاتین - Man skal ikke tro, man skal vide. Men vil man...

animo fingere = I would translate "to imagine"
to suppose = opinor, but the best ones: coniectura reperire/percipere, coniecturam capere//ducere

be certain = compertum habere
the expression "pro certo habere" means "to regard sb/sth as sb/sth.

You should express the folowing clause in ACI too, because you started it by "opusne est", so
"quod alius animo fingit" -->...

"Pro certo habere" was on my Latin-Italian dictionary, so I think it could go (you can find it, for example in Livius)...
I like your "coniecturam capere"

ACI? What do you mean by ACI?

Oh, I've just edited a post above... "pro certo habere"...

ACI- Accusativus Cum Infinitivo (don't you really use the short in Italy?)

Oh, sorry, I wanted to type:
the expression "pro certo habere" means "to regard sb/sth as uncertain.

No, we don't use the short here!
But "quod"/"what" is a relative clause, why should I put an ACI?

Wow! I didn't know that you don't use ACI short... Anyway can I use it in our discussions sometimes?

Efee, I was wrong. I thought "opusne est" is connected also with the second part, but it isn't, so no ACI anymore!!!

Of course you can use ACI!