Will is the simple future verb form. It indicates items that (with the best understanding) are going to happen.
Would is a conditional verb form. It states that something happens based on something else. Sometimes the "something else" is mentioned, sometimes it isn't.
I will attend the party.
Means I'm planning to Go to the party.
I would attend the party.
Means I'm not going to the party, unless something else is happens.
There's three special conditionals, which are compounds
- Could = would + can (it is possible, after some condition is met)
- Should = would + shall (it is certain, after some condition is met)
- Might = would + may (it can happen, after some condition is met)
And they help clarify what is expected once the condition is met. Since liking a book happens after you read it, and there's no indication that it's correct to like it, might is a better fit for your book example.
Let's see what book might fit your taste.
While a statement like
You like Asimov, so you should like this book.
Says that the liking of a book happens after you read it, but after you read this book, it would be proper to like it. So, your first statement is fine, it's just not as clear as it could be.
Let's see what book would fit your taste.
Now your second statement is odd
Let's see what book will fit your taste.
Let's see implies a non-certain future, and
will fit your taste implies a certain future.
The difference between the two statements
The answer would be 200.
It is not as easy as one would wish.
is that the first statement doesn't clarify what condition must occur to have the answer be 200, while the second statement is clear that the condition is "it is easy".
As for the two sentences about love, they both work, but one is much more practical
If I had a wish, I would wish you would love me.
Is a conditional wish (based on having a wish) that this person will love them at some point in the future based on some unspoken condition. This wish only transforms the subject to a person who will love after some condition is met. Perhaps the condition is that the subject is capable of love. Perhaps the condition it is that wisher is worthy of love. In any case, it's a wish for the possibility of love.
If I had a wish, I would wish you loved me.
Is a conditional wish (based on having a wish) that the subject loves the wisher. This is past perfect tense, so it includes some unspecified part of the past and the present. This practical wish transforms the subject to a person in love.