Being a spy, he is extremely reticent to reveal any details about who he is, where he came from, and what he’s doing, but that’s before the lasso is wrapped around him.
It makes one of its earliest appearances (if not the very first) after Steve Trevor (Chris Pine) crash lands in Themyscira.
It’s after this that he feels compelled to explain the evil plot of Dr. Maru and General Ludendorff.
We can’t say at this stage exactly how many times it will be used in the film, but being on the set of Wonder Woman I can tell you about one specific key sequence where the Lasso of Truth is put into action.