Questions & Answers about Espero que te salga bien la presentación mañana.
Because espero que triggers the subjunctive.
After expressions of hope, desire, doubt, emotion, and similar ideas, Spanish often uses:
esperar que + subjunctive
So:
- Espero que te salga bien... = I hope it goes well for you...
If you said sale, that would be the indicative, which does not fit after espero que in standard Spanish.
Compare:
- Sé que sale bien. = I know it goes well.
- Espero que salga bien. = I hope it goes well.