Do you fluently speak at least one foreign language? That’s commendable. At a meeting with a partner, where you have to deceive him, it is better to be with an interpreter.
The role of language in the occurrence of the desire to lie has been studied. And what is the result? Speaking in a foreign language, people are less likely to be tricky.
Usually, using a foreign language is less intuitive. It is also obvious: those who speak with an accent are less trusted - because they are more difficult to understand. Thus, the probability of lying is reduced.