It is not always easy to reject someone, but I guess how you would do that depends whether the connection is an online one or someone you know in your daily life. For an online connection you can become less available until the communication stops or simply ignore any further communication, it is best not to prolong this. Consider how that person has treated you when deciding to reject someone.

i understnad your feeling. and it start to diffecult for me then i changed my setting. i don`t accept invitation. it is much easier for me. i know i might losing good chance to meet new ppl. but still better than to get -non laerning language but just want to meet woman and even rude! guys messeges x(

Have you been rejected before? do just what they did to you.

allow them to reject u,they will not come again

OMG...Story of my life! I am a genuinely nice person and like to joke around (mind you, clean jokes). Guys see this as "sending signals"--even married men! (most annoying) You have to tell someone directly where your relationship stands. Tell him you like him, maybe there's a chance, or there's no way in this life. Just don't string him along, or he'll get hurt later, and you'll totally lose a friend.