I agree with everyone saying that basically you can't. You can lessen the mystery around it explaining why you did it, how you felt, etc, but there's no way to ensure people will feel "better" about it.
In my experience, I wouldn't suggest to talk about CTB while alive to people you love because it is very likely they'll become worried and anxious about you and, if you eventually decide to CTB and succeed, they could feel very guilty about not being able to "save" you. If they love you, they don't want you to leave them. That's why I like a written/recorded note more, I think it puts less pressure on loved ones.
In the end, CTB is something painful for everyone affected, so there's no way to stop the grief. But I get why are you worried about it, when someone is so familiar with pain, they wouldn't want to cause more... That's why we're here.
I hope you the best.