Hel considered Styx's offer even as she continued to go on about food and Demeter. Refusing might look like she was over-eager to see Hades. While that might be the case, she didn't need gossip getting about regarding it. If he thought she considered him a friend, as he considered her, so much the better. She'd rather have him as a friend than not at all.
Having grown up in Asgard, Hel knew well what gossiping could do to a person. And the women there seemed to take it to a whole new level. While everyone she'd encountered so far in the Greek Underworld had been kind, there was no knowing what they might say behind closed doors. Hel had trust issues, and rightly so. She didn't need uncomfortable rumors to make their way to Hades' door.
And what could it hurt to try to have another friend and ally? Though she couldn't for the life of her imagine why Hate would want to invite someone to her home. Nyx had gone on and on about her children, and how their traits did not define them, but Hel had taken that with a little salt. What mother didn't gush about their children and try to cast them in a good light?
Hers, actually.
"Thank you, that sounds fun." Really, nothing about what Styx said actually sounded "fun", but it was the best she could do to not sound too excited. That would sound false, and then Styx might wonder...
Damned if she did, and damned if she didn't. Oh well. Too late.
"Like I said, he wasn't expecting me. I just wanted to get away from home for a bit." There. That sounded convincing, at least to Hel. To top it off, she even smiled- sort of. Hel's smiles were typically not very wide as they tended to be detrimental to the fragile side of her face.