“I’ll be there” is a full sentence. Don’t add an asterisk later.

A promise made lightly is still received fully. By the time you start looking for the exit, the other person has already arranged something around your yes, and the late edit lands on them rather than on you. Reliability is built less by doing impressive things than by being where you said you would be, especially once the plan has turned inconvenient.

Before agreeing to anything, wait three seconds and picture the actual evening. If you would not want it then, say no while no is still cheap. When you do say yes, go.