How can i use variable inside Vanilla JavaScript class to make a function based on boolen

i have a JS Class which is making a function of giving a border to an element when i click to another element. That means when i click on .trigger class element, it will give a border to .content class element. But this function only should be happen based on a Boolean condition. If Boolean is Yes it should be give border, other wise i should not work. My code is works when i set the method inside the constructor parenthesis with this keyword and i can also declare variable there. But I need the method outside the constructor based on my other code. So how can i possible to declare vaiable outside the constructor and inside the class. I need this using Class approach based on my project. My code is as follows. Hope someone can help me on this. Thanks in advance!

class ParentSelector {
    constructor(trigger, content, condition) {
        this.trigger = document.querySelector(trigger);
        this.content = document.querySelector(content);
    }

    let outline = condition;

    makeOutline(){
        this.trigger.addEventListener("click", (e) => {
            if (condition) {
                e.target.nextElementSibling.style.border = "2px solid red";
            }
        })
    }    
    
}

let a = new ParentSelector(".trigger",".content", true);
a.makeOutline();

<div class="one">
<div class="trigger">Trigger</div>
<div class="content">Content</div>
</div>