It's nice to write a thank you note to your teacher in Japanese after, I'm sure your teacher will appreciate it.
ใใใใจใใใใใพใใใ
Thank you.
This is OK.
ใใชใใฏๅ
็ใใใฆใใง่ฆชๅใงใใใ
You have been a wonderful and kind teacher.
ใใชใใฏ็ด ๆดใใใใฆ่ฆชๅใชๅ
็ใงใใใ
But in Japanese, to address people with ใใชใ when you know their name does not sound natural. Especially when adressing people whose title is above you (like teachers, boss) may sound rude. It is safe to call them by the title, or name with title/honorific.
e.g.
ๅ
็ใฏ็ด ๆดใใใใฆ่ฆชๅใชๅ
็ใงใใใ
โโๅ
็ใฏ็ด ๆดใใใใฆ่ฆชๅใชๅ
็ใงใใใ
๏ผโโใใใฏ็ด ๆดใใใใฆ่ฆชๅใชๅ
็ใงใใใ๏ผ
ไปๅนดใใชใใงๆใใใใจใๆฅฝใใพใใใ
This year I have enjoyed being taught by you.
ไปๅนดๅ
็ใซๆใใฆใใใฃใฆๆฅฝใใใฃใใงใใ
๏ฝใซใปใปใปใปใฆใใใ = being ใปใปใปใปby ~
Literal translation is "This year I was taught by you and enjoyed".
ใใใ has a connotation of appreciation/gratitude in this case.
ใใใ itself means "to get/receive" and it implies receiving some kind of favour.
ใใใใใพใใใใ็งใใใชใใๆใคใ ใใใจใใใใฃใๅพใงใใใฃใจ่ชใใใใใใซใชใใพใใใ
I was afraid, but after you helped me I have become more confident.
To be afraid can be translated as ใใใใ but ๏ฝใใ is used only to describe 2nd/3rd person, but not yourself.
ใใชใใๆไผใ means (I) help you. ใ indicates its preceding word is the direct object of the verb.
To be confident is ่ชไฟกใใใ.
ใใ means "to exist"
To get/become confident is ่ชไฟกใใคใ.
๏ผๆฅๆฌ่ชใ๏ผ๏ผใใใใฃใใฎใงใใใๅ
็ใซๆไผใฃใฆใใใฃใๅพใฏใใใฃใจ่ชไฟกใใคใใพใใใ
I was afraid (of Japanese language?), but after you helped me, I became more confident.
ใใชใใฏๆฅๆฌ่ชใจๆใคใ ใฃใฆใใใใใใใ้ใ็ฅใใพใใใ
Because you helped me with Japanese, I know I will pass exams.
ใจ means "together". "With" in the above sentence means different thing, not together.
to help someone with something is ๏ฝใๆไผใ.
"to know" have several meanings, in this case it means you can tell.
In that sense, ใใใ is better wording than ็ฅใ. ็ฅใ sounds more like "to get to know".
To pass the exam is ่ฉฆ้จใซ้ใ
่ฉฆ้จใซๅใใ is more commonly used.
ๅ
็ใซๆฅๆฌ่ชใๆไผใฃใฆใใใฃใใฎใงใ่ฉฆ้จใซๅใใใจใใใใพใใใ
Because you helped me with Japanese, I know I will pass exams.
Though grammatically correct, this sentence somehow does not sound natural.
To convey what you mean to say, perhaps using ๆใ is better.
ๅ
็ใซๆฅๆฌ่ชใๆไผใฃใฆใใใฃใใฎใงใใใฃใจ่ฉฆ้จใซๅใใใจๆใใพใใ
Because you helped me with Japanese, I think I'll surely pass exams.
ใใใใจใใใใใพใใใ
Thank you.
This is OK.
ใใใฐใฃใฆใญใ