Dear Zara,
I've been thinking about what happened at the party on Saturday, and I really want to say sorry. I'm so embarrassed by the things I said, and I hated seeing how upset you looked as you left.
I'm not going to make excuses, because what I said about your job and your boyfriend was unfair and unkind. You didn't deserve it. I'd like to explain why I reacted like that, though. I've been under a lot of stress at work lately, and when you joked about me always being late, it hit a nerve. I'd also had a couple of drinks, which made me say things I didn't really mean.
I value our friendship far too much to let this spoil it. You've been there for me whenever I needed someone, and I'd hate to lose that over one silly argument.
Would you be willing to meet up so we can talk properly? We could go for a walk in the park or have coffee at our usual place whenever suits you this week. I'd really appreciate the chance to put things right.
Love,
Leila