noun, verbal noun, の adjective
The idea you see in your head is your opinion. As the dude once said... "That's just, like, your 意見, man."
The reading is all on'yomi, meaning 意 is just fine. 見's on'yomi (けん) is a reading you didn't learn with the kanji because it's so much less useful, but you do have to know it here. You've seen it with 発見 a couple levels ago, so that should help. Still, here's a mnemonic to help you remember:
In this case, just think about how Ken the samurai has an opinion on everything. Ken is such a know-it-all, and you're better off agreeing with his opinions. He's a samurai after all!
Don't hold your opinions back, please.
Even though they were my close friends, I would probably have difficulty openly telling them about this.
This is just my personal opinion, but I sometimes think that Japan is a really weird country.