How to say thank you in a letter?
 

Hello everyone. I have just returned from Japan and would like to send a small present for a family who let me stay in their house for a couple of days. I have been wondering whether there is any common phrase you should use when writing a thankyou letter. I would like to write something like: I enjoyed staying at your place very much / please accept this small gift in return for your help. I only know the phrase 'tsumaranai mono desu ga..., but I believe it doesn't sound polite in a letter. Could anyone help me? Thanks a lot

Are you writing this letter in real Japanese or in romaji?

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In Japanese

I'd just think you would write it as you say it.

有り難う (ありがとう) or to be more polite add ございます to the end.

Arigatou in it's hiragana form is ok.

If you're presenting someone with a present, you say, "douzo."

Yes, as a general rule there are nothing but common phrases used in letters in Japanese. I recommend that you not try to be very creative in a letter, especially at the beginning and the end, which is also a general rule in a conversation in Japanese. I strongly recommend that you hand-write your letter as well.

「先日は（last name + 様の）お宅に泊めていただき誠にありがとうございまし た。おかげで大変楽しく過ごすことができました。本日 恐縮ですがお礼の品を送らせていただきます。つまらな いものですがお納めいただければ幸いです。」

That would be just an example of what you'd like to say. Note that it's completely fine to use the phrase 'tsumaranai mono desuga....' in letters.

Just add a few lines both at the beginning and at the end and it will be a good, polite letter. What you should say in those places should easily be found on the net. In case you have trouble finding it, get back to me.