let's just be friends - otherwise known as the dreaded LJBF.
This statement is used by women to let a guy know that she is not interested in any sort of relationship. Frankly it usually means she doesn't even want to be friends. You are essentially not considered an attractive suitor in her mind. It is really hard to escape the friend zone, so it is better to use pick up artist techniques right away to avoid the LJBF statement.