What does Mercutio say about blind love?
Romeo and Juliet by William Shakespeare
In Romeo and Juliet, Mercutio's words in Act II on the blindness of love take on a contradictory meaning when juxtaposed with the words of Romeo from Act I:
Alas that love, whose view is muffled still,/Should without eyes see pathways to his will! (I,i,169-170)
For, the meaning of Romeo's words are that love, whose eyes are blindfolded, can still see ways to have his will done. In Act II, Scene 1, when Mercutio uses the words blind he first refers to Cupid, the "purblind son of Venus," who still "shot the arrow so well"; this statement concurs with that of Romeo. However, Mercutio's comments on Romeo that "If love be blind, love cannot hit the mark," indicate Mercutio's judgment of Romeo's inability to find the spot for his love.
Benvolio dismisses Romeo as having a liason with the moody night--"Blind is his love, and best befits the dark" (II,i,34), so indications are that the friends do not want to bother with their friend as they think his actions are frivolous and will come to nothing. It is, ironic, then, that Romeo in Act I has spoken the truth in his remark on the blindness of love, and Mercutio has also "hit the mark" with his first comment about Cupid finding his mark though blind, but misses the seriousness of the situation as he makes his second remark on blind love, just as he misjudges Tybalt in Act III.
Benvolio preceded those words of Mercutio's with these:
Come, he hath hid himself among these trees,
To be consorted with the humorous night:
Blind is his love and best befits the dark.
The guys are looking for Romeo who is not wanting to be found. Benvolio is making fun of him because Romeo's "love" for Rosaline has blinded him from the reality that she doesn't want him.
Little do Mercutio and Benvolio know that Romeo is really in love with Juliet, eyes wide open, making this statement ironic.
When Mercutio then talks about blind love not being able to hit the mark, it's another slam on the same topic essentially saying, "Romeo, you're not going to get her even though you're out there trying right now!!!"
I assume that you are talking about the part in Act II, Scene 1 where Mercutio talks some about love. In this case, he is talking to Benvolio. They are talking about Romeo.
What he actually says to Benvolio is that blind love cannot "hit the mark." When he says this, it is part of a whole bunch of relatively silly things that Mercutio says about love and Romeo and Romeo's new girlfriend (they don't know who it is).
Most people believe that much of the rest of the stuff that Mercutio says here has double meanings that are somewhat sexual.