When an item is out of stock, what makes a substitute offer feel honest?

Discusses how shops can offer alternatives without hiding price, timing, or material differences.

A substitute offer only works for me when it names the original item, explains what changed, and compares the alternative honestly. Same price, different color is easy. Different size, delivery date, material, or price needs clearer wording. If you run customer messages, what details make an out-of-stock substitute feel helpful instead of pressured?