"Thank you for your patience and instilling the confidence in me to pass the test"
"I'm a better driver now thanks to you. Thanks a million for all your help in me passing the test."
"Thank you so much for your brilliant guidance and instruction. I really appreciate it and wouldn't have passed the test without your help"
"You were the perfect driving instructor for me!"
"Thanks for all your patience, now I'm driving everywhere!"
"You made taking and passing the test a lot less daunting"
"Your pre-test lessons were crucial"