how to change comment's remind word ?

I’m afraid you won’t be able to customize the text in Jetpack Comments. The comment form is added via an iFrame, and the iFrame is hosted on WordPress.com. That makes it difficult to customize the form yourself.

At the moment, we offer 2 customization options, available under Settings > Discussion in your dashboard. There you’ll be able to change the form color, as well as the comment form greeting text. We plan on adding more customization options in the future, but I don’t have an ETA yet.

I hope this helps.

thanks for your reply ,
if i will not able to change the text of the comments .
so could i change this string : [Fill in your details below or click an icon to log in] in Chineses, or insert a string of text after it ?

You can install Jetpack in Chinese by following the instructions here:
https://jetpack.me/support/getting-started-with-jetpack/how-can-i-install-jetpack-in-my-language/

If some of the strings in the comment form are not translated yet, you can propose new translations here:
https://translate.wordpress.com/projects/wpcom/

some of the comments form has already show in Taiwan Chinese （zh-TW)
but 「Fill in your details below or click an icon to log in」still in English
if it cant transfer to in Taiwan Chinese , could i insert a word after / behind it ?

would you mind check it out my website to see my problem

Someone already proposed translations for that string, but a validator will need to validate these translations before they appear on your site.

You can read more about how translations work here:
https://en.support.wordpress.com/glotpress/

could i insert a word after / behind it ?

I’m afraid that won’t be possible, for the reasons I mentioned earlier.

okay i see
but i just wondering about how long it could be approved

That depends on the validators in charge of the Taiwanese translations. They should get to it promptly.