### Clue: Juliet had one second to tweet her answer surprisingly (10)
### Answer: SWEETHEART 
 ### Explanation: Definition: Juliet had one
 S(abbrev. for second as in "h:m:s") **plus**(to) **anagram of**(surprisingly) [TWEET HER] + A(abbrev. for answer)].
Answer: What Juliet had in Romeo, or Juliet was one herself to Romeo, depending on whether one puts the "one" in the defn. or the wordplay.