What is the ruling on compliments not intended for their true meaning, and are they considered a lie?

There is no harm in offering hospitality as a courtesy to someone passing by your house if you intend to host him should he accept. However, if you would decline his acceptance, it is feared that this would be a lie, unless an unforeseen circumstance arose afterwards and you apologized, and your apology was accepted.

A Muslim is keen on fulfilling promises and avoiding breaking them, for breaking a promise is a characteristic of hypocrisy. And whoever promises with the intention of not fulfilling it is considered a liar, unless he intended to fulfill it but then an impediment arose.

This is supported by what Abu Dawud narrated from Abdullah ibn Amir, that his mother called him to give him something, and the Prophet, peace and blessings be upon him, said to her: "Indeed, if you had not given him anything, a lie would have been written against you."