No Solo Ads sellers will or can guarantee sales. If you found one that says that, skip. However, what I will promise is to deliver traffic of the best quality from real people. This will increase your chances of closing sales with your well thought-out squeeze page and funnels.
What niches are good with your traffic?
Mainly Make Money Online, Internet Biz Opp, Crypto, and Work From Home.
What percentage of Tier 1 traffic will be delivered?
At least 90% from Tier 1 countries (US, UK, Canada, Australia, New Zealand). Most of the time is more than that.