Hi @ucsendre,
Thank you for providing additional information.
I checked your site and do noticed that the the text is not yet translated.
From the System Status Report you’ve shared, I can see that you’re using several plugins, and your theme overrides some files related to the checkout page and payments form.
porto/woocommerce/checkout/form-billing.php
porto/woocommerce/checkout/form-checkout.php
porto/woocommerce/checkout/form-coupon.php
porto/woocommerce/checkout/form-login.php
porto/woocommerce/checkout/form-pay.php
porto/woocommerce/checkout/form-shipping.php
porto/woocommerce/checkout/payment-method.php
porto/woocommerce/checkout/payment.php
porto/woocommerce/checkout/review-order.php
porto/woocommerce/checkout/thankyou.php
I recommend you temporarily deactivate all plugins except WooCommerce, WooPayments and Loco Translate, then check if the translation works.
If it does, reactivate your plugins one by one and check the site after each activation to find out which one is causing the issue.
Also, please check whether the Porto theme overrides this text or not. Just search these strings in the theme to verify it. Or, temporarily, you can switch to a default theme like Storefront to see if the issue comes from the theme.
Please let me know the results of these tests. If the issue persists, please open a ticket about this from Woo.com > My Account > Support. You may need to create an account before you can access that page.
Make sure to include a link to this thread so we know what has been done already.
Looking forward to helping you.