The phrase "a certificate attesting" is correct and usable in written English.
It can be used when referring to a document that verifies or confirms a certain fact or status, often in formal or legal contexts.
Example: "The applicant submitted a certificate attesting to their completion of the training program."
Alternatives: "a certificate confirming" or "a certificate verifying".
And, for first-timers, a certificate attesting to the first haircut.
The most difficult part was getting a certificate attesting that Lena was unmarried.
Although the grading of coins can be confusing, most United States coins sold in coin shops come with a certificate attesting to its grade from a reputable agent.
Ms. Gall has a certificate attesting to the fact that a butterfly banded in Woodbridge was captured six months later at a butterfly preserve in El Rosario, Mexico, having traveled 2,019 miles.
After I heated the milk for my final cup (wield the frothing wand so you hear a shy hiss, not loud slurps), I received a certificate attesting to barista abilities worthy of a Roman caffeinista.
This bolstered enrollment in the school, as students were drawn by the prospect of receiving a certificate attesting to their level of education.
One man lifts an arm to show a medical certificate attesting to his ill health.
The law does allow a woman to attach a statement to the original birth certificate attesting that she does not want to be contacted, but there are no legal prohibitions against an adoptee who ignores those wishes.
In case of hospital admission, the worker can send the hospital certificate (attesting to the duration of the hospital stay), followed by a physician's certificate for the recommended length of convalescence, if any.
An exemption certificate attesting this fact was issued by the IRB.
On the wall outside, a framed certificate attested to Mr. Saggoo's training in public speaking with Dale Carnegie and Associates.
