Truth or Lies

Telling the Truth is very easy, so just start a 2 player game on Normal. Keep telling the Truth until the round is over and the achievement unlocks. Refer below for tips:

How to tell the Truth:
Telling the Truth in this game is very easy. Simply sustain a single note noise as if you were singing for the entirety of the countdown during your answer. A higher note is preferred. You will get 1,000 points and a Truth every time.

Start Game -> 2 Players -> Normal
Create a new profile for either one or both of the players. When it asks if you want to calibrate, select yes! For the three lie answers, talk in a low voice. For the three truthful answers, record the sound from the Youtube video (any point in the video will work).

Now simply play this video to answer every question in the game and it will recognize it as a truthful answer. Answer every question with a truthfully in a single round and the achievement is yours.

A more ideal method to being consistent when telling the truth is to situate the microphone in front of a fan, or similar device whose noise producing ability is constant. This will record the same response almost exactly each time.

This method can be used to net multiple achievements across a "long game" allowing the player to be AFK.

I managed to get all truth for each question just by tapping the mic on my hand until the bar reached the end.

Good Luck