Sorry, this is false. There are many situations where there is actually a mitzva for the shadchan to lie.
Please lets discuss this because quite honestly, it makes me sick.
No one should be lied to. No one. Honestly, if I were on a date and found out the shadchan had lied to me, I would pick myself up and leave right away. No matter how much I liked the guy.
No one should be manipulated into dating someone. Just becauses the shadchan thinks its a great match and should go through, doesnt mean it should. And I know plenty of success stories with lying and I always feel so bad for them. I also know plenty of divorces that occured because of a shadchan lying.
So, honesty IS the best policy.