My father today asked me how much discount a particular shop gives. I said that they give a 40 taka discount if a customer buys 400 takas worth of goods. However, I am not 100% sure that the information I provided is correct. I am about 80% sure that I was correct. So, did I lie?
If the information you provided is correct, you didn't lie. If the information you provided is false but you did not know it is false, you lied but you are forgiven by Allah. ( hadith in Sunan ibn Majah 2045)
In this case, you are mostly sure that what information you have provided is correct, this does not impact if what information you provided is false and your lying
It is possible for one to be doubtful in information he provided and that the information is correct.