Most apologies fail before they are finished being read. The person receiving them can feel within the first sentence whether this is a real apology or an apology-shaped thing designed to make the discomfort go away. The difference is not about finding better words. It is about what is underneath them.
You have probably received apologies that felt hollow even though all the right words were there. "I'm sorry you felt that way" has sorry in it but is not an apology. "I'm sorry, but you have to understand what I was going through" has sorry in it and immediately takes it back. The words said sorry and the message said something else.
The formula is the problem
Most people, when they sit down to write an apology, reach for the formula. Acknowledge what happened, express remorse, offer to make it right. That structure is not wrong, but when it is followed mechanically it produces exactly the kind of apology that the other person can feel is mechanical.
A real apology sounds like you actually thought about what you did. Not like you read a guide on how to apologize. The difference comes through even in text, even in a few sentences.
Write it to them, not to the situation
One of the most common failure modes in written apologies is writing about the situation rather than to the person. "What happened last week was not okay and I regret the way it went" describes an event. It does not speak to a person.
Write to them. Use their name. Reference something specific about them or about your relationship. "You have been one of the most important people in my life for twelve years and I treated you like you were not" is not a formula. It is something you are saying to a specific person about a specific relationship.
Specificity is the most important element
If someone reads your apology and cannot tell what you are apologizing for without context, it is not a real apology. Name what you did. Say the specific thing. This is uncomfortable because it requires you to say out loud the thing you did without putting any distance between yourself and it.
That discomfort is actually part of what makes the apology work. The other person can feel that you are not hiding behind vague language. That you are looking directly at what happened without flinching. That is what accountability looks and reads like.
Do not end with a question that requires an answer
Ending an apology with "can you forgive me" or "are we okay" is understandable, but it puts the emotional labor of managing your anxiety about forgiveness back on the person you hurt. Let the apology stand on its own. Close with something that acknowledges you are there whenever they are ready, without demanding a response to relieve your own discomfort.
When you cannot find the words
The hardest part of writing a genuine apology is usually the first sentence. Once you find that, the rest often follows. unsaidit helps you find that starting point when you know what you want to say but the words are not coming. It helps you write something that sounds like you, not like a template, and gives you a few different versions to work from depending on your tone and your relationship.