Ruby on rails

I am comfortable in C and C++. what level of effort should i need to
take in order to learn Ruby on Rails in detail.

You should probably know Ruby…

What do you mean by "in detail"? Assuming that you first learnt C,
how long did it take you to learn C++ "in detail"?

In addition RoR is two things, first there is the language Ruby, then
there is the Rails framework which sits on top of Rails. How long it
takes you to become proficient in Rails will depend on whether you
have any web development experience as an understanding of html and
probably javascript will be required in order to build web sites.

If you wish to proceed I suggest taking a couple of days out and
working right through the tutorial at railstutorial.org, which is free
to use online. That will give you an understanding of the basics of
Ruby and Rails. You should then be able to answer the question
yourself.

Colin