Normal couples are actually very close friends with each other, it's the odd couples that wished to pursue something more.

As for boys wanting to pursue sexual relationship with girls they find to be attractive.

Well, first of all he need to find her attractive.

It should be noted a boy wouldn't reach a girl out of nowhere unless he has a reason to reach her. However, the reason don't necessary have to be because he think she is attractive.

A boy might have disguised his sexual interest as something else if he is lacking of self confidence.

If he has self confidence and manners, he will just subtly hinted his sexual interest, but never lied about his sexual interest.

As for girls think boys wanting to pursue them for sexual relationship.

Well, that depends on how attractive they think about themself and how much self confidence they got.

A girl who think herself as pretty have a high level of confidence, she will think boys are after her for sexual relationship. If a boy pursue her sexually eventhough he mentioned he didn't want it, she will accept it as natural.

A girl who think herself as not pretty have a low level of confidence, she will think boys don't after her for sexual relationship. If a boy pursue her sexually eventhough he mentioned he didn't want it, she will be very confused.

A girl who have a low level of confidence with a boy who have a low level of confidence, is a combination for trouble. I suggest a third party to be involved here.