Targeting a specific h3 title

Hi guys, I am using the yt shorcod plugin and although it lacks a lot of funcionality that the visual composer had, it still way better since it doesnt slow my website as much. But I was wondering how can I target a specific element on the page to add css.

This is the element I want to add specific css

https://goo.gl/photos/fKaCtvQz2fqNEps66

this is the css that I already tried but failed 🙁

h3.widget-title:nth-child(5) {
    display: none;
}

.yt-shortcode-column.col-sm-6 h3:nth-child(5) {
    display: none;
}

.yt-shortcode-column h3:nth-child(5) {
    display: none;
}

Thank you for the time. I spent an hour trying to figure this out but no luck