Bromination of an alkene in presence of water Bromination of an alkene in presence of water results in its mechanism in a cyclic bromonium ion and "afterwards $\ce{H2O}$ binds to the carbon atom surrounded by more electron donating groups."
This is what we learned in class and I couldn't understand why. Shouldn't an electron donating group decrease the "strength" of an electrophile?

Also to my surprise, in an exercise, $\ce{H2O}$ was added to the formerly $sp2$ carbon bonded to $\ce{-OCH3}$ which donates electrons by resonace in an alkene.
But $\ce{H2O}$ was added to the cyclic bromonium and not to the alkene directly! So why to care about  the resonance effect of $\ce{-OCH3}$?
While there is no formal carbocation intermediate, the cyclic bromonium intermediate has a few different resonance forms (reference):



As you can see on the right, in the structure representing the resonance hybrid, partial positive charges build up on the electrophilic carbons connected to the bromine. The carbon that is more substituted with electron donating groups has a greater partial positive charge (and therefore more electrophilic character) because of the stabilizing effect of the substituents. That's why the nucleophile attacks at the more substituted carbon.