This is actually a challenging question because she is not simple to nail down with just a couple of words and sometimes she shows a quality, and later shows the opposite quality.
1. Concerned -- she is especially concerned for Hamlet after he starts to act crazy. Her report to her father expresses he specific concerns, but that ultimate conclusion is that Hamlet is a completely different person than before. Polonius assumes that the behavior is stemming from Ophelia's rejection of Hamlet's romantic intentions, and Ophelia probably does as well. On the other hand, she broke up with Hamlet because her father told her too and willingly went along with the plan to attract Hamlet into conversation so that Polonius and Claudius could spy on them. Is she really concerned for Hamlet here? or is she just not strong enough to fight them?
2. Loving. She also expresses clear concerns in the "get thee to a nunnery scene." She seems genuinely convinced that Hamlet has lost his mind and that his reason is "sweet bells jangled, out of tune and harsh." She takes quite a bit of harsh talk and accusation, but she doesn't lash back, she takes it assuming that Hamlet isn't in his right mind. Perhaps she is trying to warn Hamlet that he is being watched when she lies about where Polonius is. On another note, she does show love or at least loyalty to her father and does what is asked of her, even if it will hurt her and relationship with Hamlet.
3. Fragile. She is clearly, and understandably fragile when we see her breakdown and suicide in Act 4. In her defence, her boyfriend has gone crazy and spoken very harshly too her, then spoken rather bawdily to her before the play, and then killed her father. It would be a lot for anyone!