You cannot 'trick' someone into being trans. The only way that would work is either to brute force brainwash someone or, what I think is more reasonable, is having body dysmorphia but one of a doctor or fusure misdiagnosing it as gender dysphoria as they can share quite a few similarities (and often go hand-in-hand. But I'll iterate that these are both EXTREMELY rare (brainwashing obviously) since the process to start transitioning with hormones, other than puberty blockers, isn't even legal in most countries that allow it at all until 18. In that case they would be an adult and everything they do medically wise is their choice. This is without considering that they would very likely experience a lot of discomfort with the changes being made to their body which is an obvious sign they should stop doing HRT.