Being an adult doesn't necessarily equate with understanding all the nuances around sex and reproduction. It doesn't help that people on her world rarely used the word 'fertility' or any of its derivatives except in the context of farming and agriculture. That Thor can help women become fertile in the hopes of conceiving a child... For all the sense it makes, it's still extremely awkward for her when he calls it out.

"N-not a problem for me," she says quickly, her face flushing a bright red. "I'm not-- I mean I don't--" Dreams she needs to stop trying to speak and just say the important part. "I've never had sex and no men have any interest in me so it's fine."

...oh dreams, that's even worse. Her shoulders tense and her eyes widen before she quickly covers her face with one hand, motioning in the direction of the plants with the others.

"Please go ahead." And cut her off from saying anything else, please. Please?