Grammar fix

strong opinion

firm belief

A strong opinion is a belief or view that someone feels very sure about and is not easily changed.

collocationB1common

Hear it in context

Notice where the phrase sounds natural.

She has a strong opinion about climate change and often talks about it with her friends.communication
In my opinion, having a strong opinion on social issues is important because it shows you care and are willing to stand up for your beliefs.IELTS speaking

Pattern: have/hold a strong opinion (about/on something)

WrongI have a strong opinion to vaccines.

RightI have strong opinions on/about vaccines.

Opinions ON or ABOUT a topic, not 'to'.

Patternhave/hold a strong opinion (about/on something)

Choose the version that sounds natural in speech.

Stiff I hold firmly entrenched views on this subject.

Natural I've got strong opinions about this.

Natural; 'firmly entrenched views' is debate-club formal.

Words that usually travel with it.

A 'strong opinion' means you feel sure and confident, while a 'weak opinion' means you are not sure or can be easily convinced otherwise.