Language is fluid, and usage changes. A case in point is the subjunctive (il congiuntivo), which in English is rapidly becoming extinct. Phrases like "I suggest you go home immediately" and "Robert wishes that you open the window" are not in frequent use anymore.
In Italian, though, the subjunctive tense is alive and flourishing, both in speaking and writing. Rather than stating facts, it expresses doubt, possibility, uncertainty, or personal feelings. It can also express emotion, desire, or suggestions. The table below provides examples of three regular verbs conjugated in the present subjunctive tense.
PRESENT SUBJUNCTIVE
PRONOUN
-ARE VERB
-ERE VERB
-IRE VERBS
che io
parli
scriva
senta
capisca
che tu
parli
scriva
senta
capisca
che lui/lei/Lei
parli
scriva
senta
capisca
che noi
parliamo
scriviamo
sentiamo
capiamo
che voi
parliate
scriviate
sentiate
capiate
che loro/Loro
parlino
scrivano
sentano
capiscano
Typical phrases that call for the subjunctive tense include:
Credo che... (I believe that...)
Suppongo che... (I suppose that...)
Immagino che... (I imagine that...)
È necessario che... (It is necessary that...)
Mi piace che... (I'd like that...)
Non vale la pena che... (It's not worth it that...)
Non suggerisco che... (I'm not suggesting that...)
Può darsi che... (It's possible that...)
Penso che... (I think that...)
Non sono certo che... (I'm not sure that...)
È probabile che... (It is probable that...)
Ho l'impressione che... (I have the impression that...)
Certain verbs such as suggerire (to suggest), sperare (to hope), desiderare (to wish), and insistere (to insist) require use of the subjunctive.
From:https://www.dbfei.com/Article/yidaliyu/201311/7708.html