appropriate gift for a guarantor?

what is an appropriate thank you gift for a guarantor?
My friend/coworker kindly offered to be my guarantor. I know being guarantor is a big stress for anyone and he is only two years older than me (30).
I want to show my gratitude and buy a present. I know a guarantor company charges one month rent but I thought an object would be more personal as money seems a bit cold hearted to me but I know in weddings and stuff people give money in envelopes so perhaps not in japan?, are there any special envelopes for situations like this to say thank you or should I go with an expensive gift of something I think he will like instead?

Normally I would object to giving a cash gift but this is one instance where I think it is acceptable.

Becoming someone's guarantor is one of the most dangerous financial decisions a person can make.

You could do a 50/50 gift/cash along with a handwritten thank you letter.

It depends on what the person likes but a designer necktie + accessories set if he works at a company, a fine bottle of wine/champagne, etc are appropriate gifts. Include a fresh 10,000 bill.

Or you could give a small gift (chocolate/cookies) and 30,000 in department store gift certificates.

I agree with the above that a gift is definitely appropriate for this situation - but a physical gift and not cash.

Given the financial commitment of being a person's guarantor, it would first be hard to figure out just how much cash to give. Guarantor companies do take 1 month's rent, but they have many other resources that enable them to make unforeseen financial commitments should the unlikely happen. So gifting 1-months rent as a thank you doesn't sound appropriate because your guarantor may have to pay many times that amount somewhere down the line.
I think a physical gift like mentioned in the above post would do a better job of symbolizing your appreciation - maybe something to adorn their own house with like a crystal piece, digital picture frame, etc.