How do you go about restoring someone's trust in you.

Not enough information here. You seem to know that your friend has lost their trust in you. You need to be clear on why or what you did for that to happen and from their you can begin to earn their trust back.

Maybe because you don’t understand what that person is going through.

With actions, not words.

Well, I suspect that unless you can open some sort of channel of communication then you wont be able to.

What @zandrace .. said. but you might want to ask them what you did.

Okay, a little more information. I made a flippant remark as a joke. (I know that will surprise a few people). Evidently it hit a little too close to home, and now my friend has pulled back and doesn’t even return my calls.

Tell them your sorry!

@slick44 That didn’t carry too much weight with them.

Act right for an extended period of time.If they won’t speak to you,try writing a letter.Good luck

Oh well sorry, at least you tried.

This probably bothers me so much because I live and die by my word. I don’t ever go back on it.

Then dont be so hard on yourself. You can only do so much, the rest is up to them.

Try to talk to your friend. Really talk about what happened. You know what the remark was. Do you know why it was so hurtful to them?

You need to explain why you made the remark. (You were nervous and just blurted it out. You never thought about what you were saying. Whatever the truth is.) Then you need to sincerely apologize.

You need to ask if there is any other thing that you have done. You need to tell your friend that you would do anything to have the friendship back.

If your friend won’t speak to you, maybe you could write them a letter.

The first thing is to ask. You can’t possibly be expected to know what happened unless you can read minds. You should be given the chance to make things right, or to say; “That isn’t what I meant.” or whatever.
Is it possible that you are operating under a mis-perception? You say that you can tell, you can’t say that any words have actually been spoken. You could be completely misinterpreting….oh. Cut off communication? Really? Maybe a cooling off period is in order.
I’d still go with finding out exactly why first. Until you know why, you can’t really address the issue.

Maybe you are reading too much into it. It takes more than a flippant remark to lose my trust and I forgive little incidents because friendship is important to me. Perhaps the person is busy, or depressed. How many times have you tried to call? If it has only been a day or two maybe something is just going on in that person’s life or something. If they really won’t answer your calls at all, then it is kind of hard to apologize. I really hope it works out. I wouldn’t jump to too many conclusions until you can get an explanation from the person.

@escapedone7 @Trillian It’s just been a little while and I did get one response. It was extremely cold.

“I have a friend”

Either it was THAT bad. Or you never really had a friend.

You can only do your best to make ammends, the rest is up to your friend.
Was the misunderstanding on your friends part for not realising it was a joke or on your part for not realising it would have such an effect?

My part for not realizing the effect it would have.

If you make it clear that its a mistake you will learn from and your friend still wont have any of it, it then becomes their problem and you are free to walk away knowing you did your best.

You have to let this person choose to give you another chance. You apologized and now they get to choose when or if they are going to forgive you, it’s officially out of your hands.