How to underline two div's consecutively?

I’ve got 2 <div>s that each gather their text from some JS that I’ve written.
But I want the end-result to look like in the following image. And I can’t figure out how to do that.

I can consolidate them into a single but then I have the issue of needing to apply two different weights to a single <div>, which also wracks my brain.

So basically I want text with 2 different font-weights to be underlined with no interruption.

I’ve tried the following, and a lot of googling:

div.parentDiv {
    text-decoration-line : underline;
}

>Solution :

Is this what you are after?

div {
  font-weight: 700;
  text-decoration: underline;
}

div span {
  font-weight: 400;
}

<div>
  Good Reviews
  <span>(30)</span>
</div>

Its hard to know with your current question, could you add your HTML and JS so we can see the whole example.