reported speech: Latin acc.+inf. ∥ Greek ὅτι-clause (saying) and infinitive (thinking)
Idiom watch: English 'reports/thinks THAT…' splits two ways. Latin ALWAYS uses acc.+inf. with no word for 'that' (hostēs … appropinquāre; urbem tūtam esse). Greek splits by verb: SAYING (λέγει) takes ὅτι + finite verb (retained pres. προσέρχονται); THINKING (νομίζει) takes acc.+inf. like Latin. The connective δέ links the second Greek sentence — Greek joins with particles where Latin and English merely juxtapose.
Real instances of this construction, mined from the PROIEL dependency treebanks (Herodotus · Cicero) — the model you are imitating, attested in the wild:
Authored pedagogical model answers, proofread for grammatical correctness in both languages. Not from a single source edition.