Tell her you have unconditional love for her. Explain that means your love will not diminish even if she has behaved in a disappointing manner. If she has lashed out at you, you can let her know that although you were hurt, you still love her as much as you ever did.

Let her know you're there for her and willing to listen if she needs someone to confide in. Many children trust their relationship with their grandparents and are willing to share their secrets, says Terri Apter, who researches family dynamics, in the Psychology Today article "Grandparenting: A Positive Face of In-Law Relationships."

Offer practical advice and help. For example, if her problems are related to drug abuse, recommend programs you have researched and refer her to websites such as TeenAnon and Rehabs. Offer to pay the expenses of the rehab center if you are financially able.

Suggest she come for a visit with you soon. A short break away from home might be what she needs to distance herself from bad influences she finds hard to resist or to help get over an embarrassing situation

List all of her positive attributes to help build her self-esteem. Tell her which of her qualities you admire, such as her determination and thoughtfulness. Remind her of specific times when you saw her demonstrate these characteristics. For example, if she came to help you when you were ill, let her know how appreciative you still are for her assistance.

Reflect upon good times you've shared together. Tell her how much you cherish those memories of time spent together over the years. Let her know how special she is to you. If you have kept a simple gift she gave you when she was younger, let her know how you still treasure it.

Give her hope for the future by telling her about a difficult time you or a family member had growing up that was overcome. She'd probably find comfort in hearing about when her parent made an error in judgment -- this could help her put her problem into perspective. However, don't disclose any family stories that you know your adult child would resent you sharing.

Be careful not to undermine the authority of her parents. If her difficulties stem from her rebelliousness toward her parents, you can offer sympathy for her frustrations, but don't criticize her parents -- even if you don't agree with their parenting methods. For example, if they're forbidding her to date a boy that you feel is acceptable, don't encourage her to see him secretly. Instead, suggest things she can say to her parents that might help change their minds about him. For example, she could let them know about accolades he's received at school or how much he's admired by his boss.