(Kalypso:) 'Earth be my witness in this, and the wide heaven above us, and the dripping water of the Styx, which oath is the biggest and most formidable oat among the blessed immortals, that this is no other painful trial I am planning against you […]' (5.184-187)
It's a little hard to take the gods' rules seriously when they don't seem to abide by any recognizable code of conduct. But here, Kalypso sees to be acting on the level: she's promising Odysseus that her help is genuine.
(Kalypso:) ‘[…] but if you only knew in your own heart how many hardships you were fated to undergo before getting back to your country, you would stay here with me and be the lord of this household and be an immortal […].’ (5.206-209)
Kalypso has a point – Odysseus intentionally chooses suffering. In this, he parallels Achilleus, the hero of The Iliad, who faces a choice between a long life back home and a short, glorious life fighting at Troy—and chooses Option II. And yet, Odysseus’s suffering is for the sake of getting back home—exactly what Achilleus rejects.
(Kalypso:) ‘How is it, Hermes of the golden staff, you have come to me? I honor you and love you; but you have not come much before this. Speak what is in your mind. My heart is urgent to do it if I can, and if it is a thing that can be accomplished. But come in with me, so I can put entertainment before you.’ So the goddess spoke, and she set before him a table which she had filled with ambrosia, and mixed red nectar for him. (5.87-93)
Even the gods have traditions of hospitality between one another.