The spammers are hoping for that...
They buy their stock first, or get it from the company for some real or imagined service (e.g. 'marketing' or PR); *then* send the spams, and are poised to sell as soon as it climbs - depends on the stock but often they'll be dumping at anything over 10%-20% rise, and they're trying to sell while it's still rising (far easier!).
The idea is that punters see it rising, think it's for real, buy more (which helps the price rise more)... and then no one else is taken in by the spam, and the party stops within a day or so.
If these are sparsely traded penny shares, or on an unregulated market like the Pink Sheets (like Ofex but worse, basically a private market) they'll maybe do 100x their normal volume for a few days and then revert to nothing, so you risk having real trouble even finding a buyer, still less at a profit.
Don't be fooled. If anyone really knew of a sure money-making opportunity, they wouldn't be shouting it on millions of emails... unless that IS the opportunity.