Prufrock spends almost the entire poem despairing over whether or not he should ask his mysterious question.  He is undecided.  He goes back and forth.  He ponders and mulls, hos and hums about it.  He struggles with the weight of what he wants to ask, pitted against his own incredible insecurity and social paranoia.  He really wants to ask, and imagines the scenarios in which he could do it.  But after quite some time, he concedes that he isn't courageous enough.  Who is he kidding?  He can sit there and dream about asking her all that he wants to, but he knows that he never will.  He finally admits this point when he declares, "No!" and admits that he is "no Prince Hamlet, nor was meant to be."  Instead, he is better suited as "an attendant lord," someone in a play who is there, in the background, nameless, performing orders, while the more interesting, handsome, charming and eloquent popular people (like Hamlet in his castle) go about doing all of the daring deeds with style and panache.  He declares himself "cautious...a bit obtuse...a Fool."  This is a disheartening realization to admit to oneself.  It is like saying, "Yep.  I'm a loser.  I admit it."  And then, like the loser-y self that he feels, he says that he wants to just fade into the distance.  He sees that he will always be one of those men enchanted by beautiful women (he compares them to "mermaids singing, each to each"), but that he will never actually talk to them, connect with them, or have any part in their lives ("I do not think that they will sing to me).  Instead, he'll live in his little fantasy world where everything is comfortable and he doesn't actually have to make real human contact, because that is too terrifying ("human voices wake us, and we drown").