The sentence 'I certainly appreciate it' is correct and usable in written English. You can use this phrase when you want to express gratitude after someone has done something for you. For example, if a co-worker gave you some helpful advice, you could say, "I certainly appreciate it.".
PEYTON He was there and I certainly appreciate it.
I'm not a religious person, but I certainly appreciate it when music strives for the heavens.
I'm not sure I deserve all your love today but I certainly appreciate it.
So it will be interesting to see where this book goes from here, but I certainly appreciate it as an individual.
From the first paragraph onward, I certainly appreciated it — "The Pugilist at Rest" seemed to me a small masterpiece, vividly imagined, wonderful in all ways.
"If you could bear that in mind while I'm on, I'd certainly appreciate it".
CONGRESSMAN CHAFFETZ: -- I would certainly appreciate it.
Thanks to Ludwig my first paper got accepted! The editor wrote me that my manuscript was well-written
Listya Utami K.
PhD Student in Biology, Bandung Institute of Technology, Indonesia