The SweetAlert repo seems to be unmaintained. There’s a bunch of Pull Requests without any replies, the last merged pull request was on Nov 9, 2014.
I created SweetAlert2 with HTML support in modal and some other options for customization modal window – width, padding, Esc button behavior, etc.
Swal.fire({
title: "<i>Title</i>",
html: "Testno sporocilo za objekt: <b>test</b>",
confirmButtonText: "V <u>redu</u>",
});
<script src="https://cdn.jsdelivr.net/npm/sweetalert2@11"></script>