All it says, substantively, is "how can I conceive, seeing as how I am not in a "relationship". Where you get the idea of ascending into Heaven without dying, out of this verse, is a great mystery.
No, it does not make sense. A girl is betrothed; if she intends to marry and have marital relations, that is how she'll conceive. No need to ask any questions.
Assumption of Mary is indeed not following from this verse. Her perpetual virginity is.