It's important to use language correctly when you're presenting. Here is a great post from Lynn Gaertner-Johnston's Business Writing Blog on how to avoid mistakes when using assure, ensure and insure:
http://www.businesswritingblog.com/business_writing/2012/01/to-assure-you-about-assure.html
Gilda Bonanno's blog www.gildabonanno.blogspot.com
http://www.businesswritingblog.com/business_writing/2012/01/to-assure-you-about-assure.html
Gilda Bonanno's blog www.gildabonanno.blogspot.com