The Subjunctive for Emotions
You have already learned to use the present subjunctive to express rules and necessity. Another major use of the subjunctive is to express subjective emotions—such as hopes, fears, joy, and sadness.
When your main clause expresses a feeling and is connected to a secondary clause by que (that) with a different subject, the verb in the secondary clause must be in the subjunctive mood.
Expressing Fear and Annoyance
To discuss worries or relationship issues, you will frequently use verbs like recear (to fear) or phrases like irrita-me que (it annoys me that). Because your emotion is directed at someone else's actions, the following verb takes the subjunctive.
Impersonal Expressions of Emotion and Possibility
Just like you use impersonal phrases for necessity (é preciso que), you can use them to state an emotional reaction or an opinion. Expressions like é bom que (it is good that) or é triste que (it is sad that) trigger the subjunctive. The same applies to expressions of possibility, such as é possível que (it is possible that).
Note on pronouns: In subordinate clauses introduced by que, any reflexive or object pronouns are pulled immediately before the verb.
Hopes, Regrets, and Disappointments
Other common emotional triggers include esperar que (to hope that), lamentar que (to regret that), and ter medo de que (to be afraid that). Notice that ter medo is typically followed by the preposition de before que.
Remember that you form the present subjunctive by taking the eu form of the present indicative and swapping the ending vowel. This applies even to slightly irregular verbs: desiludir (to disappoint) becomes desiluda (from eu desiludo), and trair (to betray) becomes traia (from eu traio).