If your boss asks your opinion, you should tell your boss your opinion.
"Tell me" is an instruction. It doesn't tell your boss your opinion. So it doesn't respond to the boss in a meaningful way. It would be rude.
You can't use "Tell me" like that.
Boss: I think we should raise the price. Mely?
Mely: I think that's a good idea./ I don'...
As a native Engish speaker I don't recognise a bald "Tell Me" as a standard response and I'm not sure what your intention is.
Boss: I think we should take option X, it seems to be most cost-effective. Mely?
I guess that's a request for you. Mely, to state your opinion. In my eyes this somewhat informal, but perhaps normal in your culture. I might ...