Here are a few polished versions you can use: Fast payment, sincere and polite buyer. Arrived on time and transaction was smooth. Highly recommended! Great buyer to deal with — fast payment, sincere, polite, and punctual. Thank you for the smooth transaction! Pleasant transaction with a sincere and polite buyer. Payment was fast and buyer was on time. Recommended!

Fast and decisive

Fast and decisive.

Easygoing buyer

Fast and decisive

Easy going, kept his word, genuine buyer

Easygoing buyer

Amazing chat

Nice buyer. Thanks!

Fast and decisive

Good communication

Nice buyer, recommended