In Much Ado About Nothing, Shakespeare shows how easily people in love can be manipulated.

Claudio falls in love with Hero at first sight, which is not an unusual occurrence in many of Shakespeare's plays. What is also not unusual in Shakespeare's plays is that the course of love-at-first-sight never seems to run smooth.

Claudio confesses to Don Pedro that before he went to war he had lustful feelings for Hero, but now that he's returned from war, his feelings toward Hero have turned to love.

Apparently without having been asked to do so, and for no clear reason, Don Pedro offers to speak to Hero on Claudio's behalf and then to appeal to Hero's father, Leonato, for his consent for Claudio and Hero to be married.

DON PEDRO. I will assume thy part in some disguise
And tell fair Hero I am Claudio,
And in her bosom I'll unclasp my heart
And take her hearing prisoner with the force
And strong encounter of my amorous tale.
Then after to her father will I break;
And the conclusion is, she shall be thine. (1.1.281-287)

Long story short, Don Pedro manipulates Hero and wins her heart for Claudio, and he also wins Leonato's consent to the marriage.

Don Pedro's brother, Don John, conspires with Borachio, a drunkard, and Hero's maid, Margaret, to manipulate Claudio into believing that Hero is unfaithful to him. Claudio falls for the ruse. He doesn't speak with Hero about it, but he waits to shame Hero in front of a church full of people on their wedding day. Claudio leaves Hero at the altar, and Hero faints.

Meanwhile, Beatrice and Benedick have been in love with each other since nearly forever, but they have a funny way of showing it. When they're together they continually antagonize and insult each other.

Don Pedro, Claudio, and Leonato conspire to manipulate Benedick into declaring his love for Beatrice. Hero and Ursula likewise conspire to manipulate Beatrice into declaring her love for Benedick. Benedick falls for it, and so does Beatrice.

BENEDICK. This can be no trick. The conference was sadly borne... Love me? Why, it must be requited. I hear how I am censured. ...When I said
I would die a bachelor, I did not think I should live till I were married. Here comes Beatrice. By this day! she's a
fair lady: I do spy some marks of love in her. (2.3.201-222)

BEATRICE. ...Can this be true?
Stand I condemned for pride and scorn so much?
Contempt, farewell! and maiden pride, adieu!
No glory lives behind the back of such.
And, Benedick, love on; I will requite thee,
Taming my wild heart to thy loving hand.
If thou dost love, my kindness shall incite thee
To bind our loves up in a holy band;
For others say thou dost deserve, and I
Believe it better than reportingly. (3.1.109-118)

It was all so easy.

Shakespeare tells us a great deal about relationships in Much Ado About Nothing. He particularly shows us what character traits are necessary for people to possess in order for relationships to be successful, such as trust, forgiveness, and lack of pride.

The importance of trust is especially portrayed through Claudio and Hero's relationship. Twice Claudio allowed himself to be tricked into believing that someone he loved had questionable character by a person that he already knew had questionable character. The first time he was tricked, the morally questionable Don John led Claudio to believe that Claudio's dear friend Don Pedro had deceived him and is courting Hero for himself instead of keeping his promise and courting her for Claudio's sake. We see Claudio being gullible enough to be duped in this manner when we see him proclaim:

'Tis certain so; the prince wooes for himself.
Friendship is constant in all other things
Save in the office and affairs of love. (II.i.152-154)

Had Claudio persevered in trusting his friend whom he loved, he never would have allowed himself to be duped by Don John. Of course, Claudio allows himself to be duped a second time as well, this time allowing himself to believe that Hero has been unfaithful. Again, had he allowed himself to trust his instinctual beliefs about Hero's modesty and virtue and to question Don John's character, he never would have allowed himself to be duped this second time, showing us just how important trust is in relationships.

We see Shakespeare show us how important forgiveness is in relationships when we see Hero forgive Claudio for his atrocious behavior. Instead, she allows herself to be born anew through forgiveness and proceed with the wedding. We see Hero proclaim her rebirth in her lines:

And when I lived I was your other wife; ...
And when you loved you were my other husband.
...
One Hero died defiled; but I do live,
And surely as I live, I am a maid. (V.iv.61-66)

Hero's ability to forgive and be reborn anew shows us just how vital forgiveness is in maintaining relationships.

The importance of lack of pride is exhibited through both Beatrice and Benedick. Both are criticized for being too prideful and led to believe that the one will not proclaim his/her love for the other because the other is too proud to reciprocate. However, we see Benedick denounce his pride in the lines:

I did never think to marry. I must not seem proud. Happy are they that hear their detractions and can put them to mending.(II.iii.207-209)

Likewise, we see Beatrice denounce her own pride when she proclaims:

Contempt, farewell! and maiden pride, adieu!
No glory lives behind the back of such.
And, Benedick, love on; I will requite thee. (III.i.111-113)

Hence, since both Bendick and Beatrice decide to denounce their pride in order to be united, we see from this that lack of pride is an essential character trait in a relationship.