Solution:
You are using double quotes in your span tags, which is closing the append() method too early, since it is using those same quotes. You must either use double quotes (“”) or single quotes (”) in the jQuery method and use the opposite for any HTML code you’re appending that contains quotes.
You also forget to end and begin the content with quotes, before and after the JS variable, which will cause the issue of not being able to display the variable contents to the page (it’ll be rendered as plain text). Below is what the valid JavaScript should instead look like in your case.
jQuery(this).append('<span class="more-text">' + removedStr + '</span>');
jQuery(this).append('<a href="javascript:void(0);" class="read-more more">' + moretxt + '</a>');
In the above example, the double quotes have been replaced with single quotes to allow you to use double quotes in the HTML content. The HTML content is surrounded by single quotes to allow for the JavaScript variables to output as they should.
Heads up, remember to escape the single quotes in the jQuery, as in your case, it’ll interfere with your PHP tags.