Tu en vaut la peine

Question

Translates as 'You're worth it'. That may be how it is used colloquially but doesn't it really translate as 'You're worth the grief?'

Céline Pickard · Accepted Answer

Bonjour Chris,
That's right! The French word "peine" comes form the Latin word "poena" which means "punishment/penalty". Over time, "la peine" has evolved from "suffering" and then "trouble/effort/pains taken". According to l'Académie française:
Xe siècle : au pluriel, poenas, penas, "souffrances" 
XIe siècle : peine, "mal que l'on se donne pour un idéal"
XIIe siècle : au sens de "punition, châtiment"
 
I hope this is helpful.
Bonne journée !

Maarten Kamp · Answer

Chris, 
I think you can understand the expression with either or both of the following explanations  : 
1. The expression as ‘ valoir la peine de qqc ‘ - hence ‘ en ‘ placed before the verb ‘ valoir ‘ replaces the phrase ‘ de qqc ‘, when ‘ de qqc ‘ is known.
https://www.larousse.fr/dictionnaires/francais/peine/59016 
2.  ‘ en valoir la peine ‘ - a fixed, idiomatic general expression, without specifically needing to state what ‘ de qqc ‘ is. 
https://www.wordreference.com/fren/valoir

chris wallis · Answer

Can I ask what the 'en' is doing there.? It might simply be Tu vaut la peine?