Questions & Answers about Tu opinión me importa mucho.
Because tu without an accent is a possessive adjective: your.
- tu opinión = your opinion
Tú with an accent is the subject pronoun meaning you.
- Tú hablas = You speak
So in this sentence, tu is correct because it is describing opinión.
Because Spanish stress rules would normally make a word ending in -n stressed on the second-to-last syllable. But opinión is stressed on the last syllable: o-pi-nión.
The written accent shows that irregular stress.
It also helps you pronounce it correctly:
- o-pi-NYON