The overwhelming majority of all human beliefs are (trivially) true. Things like "If I drop a rock, it will fall down", "If I touch hot fire it will hurt", etc. and "I am sitting down", "I am typing on a keyboard", etc.
The human brain has evolved to determine truths about the world around it, especially in cases where the knowledge directly affects survival chances ("Tiger is dangerous"), but also for cases where the knowledge could help indirectly (basically all human progress including first tool usage -- achieved especially through curiosity and strive to find truth). It fails catastrophically in some cases, but most of the time it does an excellent job.
I feel a bit icky when reading both versions. A slightly less icky version would be: "... that stubborn but lovable species, the American partner." I really dislike the idea of treating the two sexes as separate species, especially given how much people already do this.
I also kind of dislike the idea of training your partner like that because it feels manipulative, but that is mostly a question of how you use it. As long as you only do it on behaviours that your partner agrees are good/bad and want to do more/less, it's fine with me. In other words, only when you know they would consent or when they have consented.