As soon as you get to a bonfire to save progress and heal, you can choose to train by selecting "Sparring Practice". Follow along with the training and spar with the protagonist's wife. By winning the sparring session, you will earn this achievement.
For all achievements in the game, you can follow this awesome guide on YouTube:
All credit to Trophy Tom. Please like or subscribe to support him. Please note how he has conveniently labeled sections of his video based on which achievement is next or what item you are tracking down, this can be seen if you watch his video on YouTube on the video progress bar instead of the imbedded video here on True Achievements. It is a very well done 100% guide.
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