Dear …
Please allow this letter to serve as confirmation that __(Full Name)__ has successfully completed the __(type/name of program)__.
__(Name)__ clearly has a good attitude towards __(subject of which he/she has a good attitude toward)__ . It was impressive to see how well__(he/she)__ immediately __(involved/immersed/etc.)__ __(himself/herself)__ __(in/into)__ the __(project/course)__ and I must say it was quite refreshing to see __(someone/a student/etc.)__ who possesses that degree of responsibility. It’s evident that __(Name)__ takes a real interest in __(briefly describe what he/she takes an interest in)__ as demonstrated not only by how well __(he/she)__ successfully completed the program, but by __(his/her)__ positive mannerism throughout.
__(Name)__ appears to be an individual who strives __(for excellence/to make a difference/etc.)__ in all that __(he/she)__ does. That combined with __(his/her)__ outgoing and friendly personality makes __(him/her)__ a real pleasure to __(work with/teach/etc.)__. I genuinely wish __(him/her)__ well.
Sincerely,