To soften a claim, use quizá or tal vez before the verb and put that verb in the subjunctive, or shift the main verb into the conditional. The more distance you want, the further you move from the plain indicative.
Examples
- Tal vez sea la opción más razonable.
- Perhaps it's the most reasonable option.
- Yo diría que el problema es otro.
- I'd say the problem is a different one.
- Convendría que revisáramos los datos antes de publicarlos.
- It would be advisable for us to review the data before publishing it.
The mistake to avoid
The subjunctive only follows quizá/tal vez when they come first - "Es, quizá, la mejor" and "A lo mejor es" both stay indicative.
Where this fits in
Estilo y registro, Spanish C1: Master idiomatic versus formal Spanish, hedging, and discourse markers to shift fluidly between colloquial and academic registers.