Send ✿ for a HAPPINESS headcanon.
She's outwardly a very happy person, but of course deep down she's unhappy. Robin doesn't let it show often, preferring to smile and enjoy the life she has now.
Genuine happiness for her is often found from reading or exploring ruins, sure she laughs and smile at the crew. Who wouldn't when you have Luffy as captain? Robin is simply happiest when doing what she's set out to do.
Send ϡ for a MENTAL STATE headcanon.
She'd be stable but could very well be teetering on the edge of unstable. The unstable probably would stem from how she crew up, on the run and killing when she needed to. Robin will question if it's right to enjoy it so much when she's snapped a person's spine, most of the time she answers yes.
Send ღ for a LOVE/SEXUALITY headcanon.
It's not often for her to think about love, Robin of course loves the Strawhats, but that's not the love she may want one day. She possibly had flings when she was on the run, if she found someone who wouldn't want to turn her in long enough to get frisky.
Though as a lover, she'd only want the utmost respect between them. Building on trust, before she even agrees to anything she will need to trust you. She never felt real love, so pushing her into anything is likely to end up her threatening to snap their neck. Robin won't let go without a reason, once her's, there won't be any breakup without a valid reason
