Well,
First of all B1/B2 visa commonly called as tourist visa can not be sponsored. So anybody visiting on that visa has to show significant ties with his/her home country( economical , social, familial etc) . Your invitation letter will just provide them a valid reason to visit USA. Having said that, if you have good income and have abided by all the rules in the USA (like tax retuns, no criminal records etc) that will help to convince the visa officer that whoever you are inviting may also be a law abiding citizen.