The morality of the situation is kind of beside the point. Iran is either being truthful or they are not. That doesn't change regardless of if they are the side of good or the side of evil.

> Why trust a US company when the US helped Israel attack Iran while in negotiations ?

Potentially. However given that whatsapp/meta is just one random american company that is already banned in Iran (afaik) it seems like that would be a really random action if it was purely about retaliating against usa.