> “I know you really want to like these jeans, but I think they fit such and so.”

This statement is empathetic only if we assume a literal interpretation of the "do those jeans fit me?" question. In many cases, that question means something closer to:

"I feel fat. Could you say something nice to help me feel better about myself right away?"

> There is no need empathy to require lying.

Empathizing doesn't require lying. However, successful empathizing often does.