WordPress is great free software in order to create websites and easly update by the users. However like any other softwares it has it’s own limitations.
Normally you would use <p> tag in order to make a new paragraph. However WordPress ignores <p> tags and <br> tags in most cases.
If you write about this problem in any search engine like this:
Why WordPress <p></p> and <br /> tags does not work properly in in posts and pages? You will find some links, discussing about this issue.
CSS often does not fix the problem, I have tried. However sometimes </br> tag is fixing the issue.
Use this tag at the end of your sentence </br>
So if you want space between two paragraph you can use </br> tag to give a space.
Or you might try creating a CSS class for that particular paragraph/sentence:
and implement to the sentence like this:
<p class=”red”>Big red sentence</span>