Here is an equation. A is in love with B , But B only likes A, but not in love with A. You should understand here the difference between love and like. When a person say they like you, it is not equal to or almost equivalent to loving you. Both are different. So get yourself cleared when some one says they like you :) . Coming back to the equation again, B only likes A. A is disappointed with B because B is not understanding or accepting the love of A. But B has its own valid reasons not to accept A.
To make this equation little complex, here comes C. C knows A is in love with B. In spite of that, C is loving A, like how A is loving B. When all the three comes to know about each other, what stance should they take?
A knows the pain of waiting for B. So A can easily understand how C will feel. Understanding C, should A accept C's Love?
Sticking to its stance, should A go ahead and keep on waiting for B? Doing this A is reacting to C, the same ways how B is reacting to A..
C knowing what love is, should it help A in its love for B?
B, coming to know C's love with A, should persuade A to accept C?
What will be your stance if you were A, B or in C's position?