What evidence is there that Lord Capulet truly loved his daughter?

Although Lord Capulet becomes frustrated and enraged with Juliet in Act III, Scene 5 when she refuses to marry Count Paris, Shakespeare gives his audience three examples of Capulet's love for his daughter. Right away, in Act I, Scene 2, Capulet expresses his devotion and sense of loyalty to his only child. When Paris asks to marry Juliet, Capulet can think only about his daughter's feelings. Even though marrying his daughter to the Count would be wise politically (Paris is a relative of Prince Escalus) and economically (since Paris is a Count, he probably has wealth), he considers his daughter's position, first arguing that she is too young:

My child is yet a stranger in the world.
She hath not seen the change of fourteen years.
Let two more summers wither in their pride
Ere we may think her ripe to be a bride.

When Paris persists, claiming that other girls Juliet's age are already mothers, Capulet then urges Paris to win Juliet's love:

But woo her, gentle Paris, get her heart;
My will to her consent is but a part.
And, she agreed, within her scope of choice
Lies my consent and fair according voice.

Capulet is taking a sensible approach to Juliet's well being, and this scene seems to indicate that he truly loves his daughter and only wants what's best for her. Later in the play, when he changes his mind about the marriage to Paris, he is again doing it for Juliet. He mistakenly believes that Juliet is in terrible grief over the death of Tybalt (she's actually grieving over the banishment of Romeo) so he believes a marriage to Paris will provide a "day of joy" for the family after such a devastating loss. That Capulet ends up berating Juliet and threatening her is more an indication of his frustration than a lack of love for Juliet. Even the most even tempered fathers sometimes become angered by their children's attitudes, especially when they feel as though they have the child's best interests at heart.

A final example of Capulet's love for his daughter appears in Act IV, Scene 5, when he shows genuine grief when he believes Juliet to be dead. He is definitely distraught at losing his only child. He bitterly expresses the feelings of a man who has lost all of his hopes and dreams:

Despised, distressèd, hated, martyred, killed!
Uncomfortable time, why cam’st thou now
To murder, murder our solemnity?
O child! O child! My soul and not my child!
Dead art thou! Alack, my child is dead,
And with my child my joys are burièd.