いかにも (Ikanimo), similar to 本当に (hontou ni), is used when you want to express that you really believe what you say. Difference between the two is merely the level of formality… meaning that it is a slightly more polite way to say 本当に. It usually comes in a pair with a statement of conjecture. Meaning that something really seems a certain way, or you really feel a certain way about something.