Really speaking

“Really speaking she isn’t very brilliant.”
Is this sentence OK?
If it is wrong, how could I correct it using ‘really’?

It’s okay but quite informal.

How could I make this sentence formal?

She isn’t very brilliant, really.

wrong.she is not brilliant really

“isn’t” is the contracted form of “is not”.
“very” is used here as a quantifier so leaving it out changes the meaning slightly.

Can I write as below omitting the comma?
She isn’t really very brilliant.
She isn’t very brilliant really.

Here, i am writing a topic on carbon emission. Kindly correct if you will get any mistake in the sentences.
Now-a- days gradually green house gas (GHG) increases day by day, due to transportation, industry etc. There are so many GHGs i.e CO2, NO2 etc. When sun radiation falls on the earth surface some proportion is kept by C02 for keeping the warm of the earth surface but excess of Co2 is not good for us. Its gradually increases, which impact on the river and also global warming. now our aim is to reduce the CO2 gas by re usability of the product. This is one of the method for reducing CO2. Now a days companies are focusing on re manufacturing.