What is the difference between positive assurance and negative assurance?

In Reasonable assurance engagements the opinion is given in positive form of expression. Hence the widespread use of positive assurance where the correct use is “positive expression of opinion under assurance” or “assurance expressed in positive form”

In Limited assurance engagements the opinion is provided in negative form of expression. Hence the widespread use of negative assurance where the correct use is “negative expression of opinion under assurance” or “assurance expressed in negative form”