How do I know when to use the subjunctive in Spanish?

Answer 1

The subjunctive mood is used to talk about:

1. Desires
2. Doubts
3. Wishes,
4. Conjectures (inference formed without proof or sufficient evidence),
5. Possibilities.

References:

1. https://www.spanishdict.com/guide/subjunctive-vs-indicative-in-spanish
2. https://www.merriam-webster.com/dictionary/conjecture