The quote is from "A Midsummer Night's Dream" by William Shakespeare.
It's meaning is simple: True love always encounters problems or difficulties, a theme that Shakespeare repeats several times in various plays. This play is one of Shakespeare's comedies, about a group of lovers who spend the night being pranked and taunted by fairies. The attitude of the play can be summed up in a famous line from Act 3 scene 2, the character Puck speaking to Oberon, "Lord, what fools these mortals be!"