How can a woman ascertain the virginity of her hymen after experiencing sexual assault in her childhood?

A woman is not permitted to allow anyone to view her major awrah to verify the presence or absence of virginity. She must repent to Allah Almighty if she did that willingly after reaching puberty, by regretting it and resolving not to return to it, and by adhering to what the Shariah has enjoined regarding interaction with mahrams and others.