<human>: Can you condense the text into three sentences or less?

I want to avoid the inevitable debate about the circumstances and go straight to the advice, so I will summarize with this: I recently made a huge mistake of lying to my boyfriend about something I didnt need to lie about and should've just been open about. Assuming I deserve to be forgiven, what can I say to let my BF know that I am completely committed to him and that I am worthy of his trust? 
To clarify, I'm not looking to use someone else's words-obviously this message needs to be from the heart. But I worry that saying the same cliche- "It wont happen again" line isnt enough and I'm not that great at expressing my emotions. 

What has your SO said after screwing up that made you believe that he/she really was sorry and that it wont happen again?
<bot>: Because I lied, I need to express to my BF that I am committed and worthy of his trust. What can I do/say to right this?