It is not possible for a company to give you a guarantee that your site will get a special search engine position.
If a company provides you that guarantee, please take a look on their offer. They may list your site in high page rank position but they will implement some valueless keywords for you site. Your site may show good results for those keywords but it will not bring business and traffic for your site.
Yes an expert, experienced SEO company may help you to uplift your listings but they can not guarantee you for a certain posi
tion. But still if they tell you that they can do so. Then surely they will use some black formula to increase your site rankings. But it will do worse in the long run. Your site may be listed in a high rank result for a month but after that you will surely be black listed by search engine authority due to the unethical staffing for your site.
The best way to get the high page rank is. Build your site to your user. Not for the search engine. Take some special ethical help from a SEO expert and follow his guidelines. Your site will click.