Looking on the internet deeply has found these results:

i certainly understand your concern. is the most popular phrase on the web.

iI certainly understand your concern. 10 results on the web	i certainly understand your concern. 11,190 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	... the policy will be more than I can afford." A basic policy for apartment insurance costs about $10 per month. Though I certainly understand your concern. R : I certainly understand your concern for your son. thechildren.com. thechildren. com. R : Je comprends tout � fait votre inqui�tude au sujet de votre fils. Jan 29, 2016 ... Scott, I certainly understand your concern about the potential for either conflict in terms or questions over whether the list is exhaustive. Oct 26, 2015 ... Nutritional Aesthetician: I certainly understand your concern, and trust me, you're not alone! What you're describing definitely sounds like�...

iI certainly understand your concern.

10 results on the web

i certainly understand your concern.

11,190 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

... the policy will be more than I can afford." A basic policy for apartment insurance costs about $10 per month. Though I certainly understand your concern.
R : I certainly understand your concern for your son. thechildren.com. thechildren. com. R : Je comprends tout � fait votre inqui�tude au sujet de votre fils.
Jan 29, 2016 ... Scott, I certainly understand your concern about the potential for either conflict in terms or questions over whether the list is exhaustive.
Oct 26, 2015 ... Nutritional Aesthetician: I certainly understand your concern, and trust me, you're not alone! What you're describing definitely sounds like�...