Why does Ophelia reject Hamlet?

Ophelia is caught in the middle of the conflict between Hamlet and her father, Polonius, who is also the chief counselor to King Claudius.

Hamlet is deeply affected by the death of his father and the remarriage of his mother to his uncle, and his behavior becomes erratic and unpredictable. Ophelia is warned by her father not to trust Hamlet and to break off her relationship with him, which she does. However, it is not clear if she is rejecting Hamlet of her own accord or if she is doing so because she feels she has no choice given the circumstances.

Additionally, the play portrays Ophelia as being a passive character who is largely influenced by the actions and decisions of the men in her life. So, the rejection of Hamlet can also be seen as a result of her lack of agency and her inability to make decisions for herself.

At Polonius’ bidding, Laertes warns Ophelia that Hamlet's love for her may not be genuine. Laertes cautions Ophelia to be wary of Hamlet's advances and to keep her heart and chaste treasure safe from his "unmastered importunity." He advises her to fear Hamlet and to keep her beauty and virtue hidden, as even virtue itself is not immune to calumnious strokes. Laertes' warnings are further reinforced by the fact that Hamlet is subject to a "vicious mole of nature" which can lead to him breaking down the "pales and forts of reason" and engaging in habits that are too much out of the ordinary. Additionally, Laertes' own anger and grief over his father's death, and his desire to avenge him, further causes Ophelia to fear that Hamlet's love for her is not genuine and that it is instead a result of his own inner turmoil.

LAERTES

For Hamlet, and the trifling of his favor,

Hold it a fashion and a toy in blood,

A violet in the youth of primy nature,

Forward, not permanent, sweet, not lasting,

The perfume and suppliance of a minute,

No more.

OPHELIA  No more but so?

LAERTES  Think it no more.

For nature, crescent, does not grow alone

In thews and bulk, but, as this temple waxes,

The inward service of the mind and soul

Grows wide withal. Perhaps he loves you now,

And now no soil nor cautel doth besmirch

The virtue of his will; but you must fear,

His greatness weighed, his will is not his own,

For he himself is subject to his birth.

He may not, as unvalued persons do,

Carve for himself, for on his choice depends

The safety and the health of this whole state.

And therefore must his choice be circumscribed

Unto the voice and yielding of that body

Whereof he is the head. Then, if he says he loves

you,

It fits your wisdom so far to believe it

As he in his particular act and place

May give his saying deed, which is no further

Than the main voice of Denmark goes withal.

Then weigh what loss your honor may sustain

If with too credent ear you list his songs

Or lose your heart or your chaste treasure open

To his unmastered importunity.

Fear it, Ophelia; fear it, my dear sister,

And keep you in the rear of your affection,

Out of the shot and danger of desire.

The chariest maid is prodigal enough

If she unmask her beauty to the moon.

Virtue itself 'scapes not calumnious strokes.

The canker galls the infants of the spring

Too oft before their buttons be disclosed,

And, in the morn and liquid dew of youth,

Contagious blastments are most imminent.

Be wary, then; best safety lies in fear.

Youth to itself rebels, though none else near.

OPHELIA

I shall the effect of this good lesson keep

As watchman to my heart. But, good my brother,

Do not, as some ungracious pastors do,

Show me the steep and thorny way to heaven,

Whiles, like a puffed and reckless libertine,

Himself the primrose path of dalliance treads

And recks not his own rede.