You hoped it was a fleeting romance. But now that your BFF is flashing some bling and waxing poetic about happily ever after, you fear her walk down the aisle is destined to end with a trip to divorce court. Are you being a good friend if you speak up or should you just mind your own business?It depends. Make sure you're prepared before you object. “This may indeed be the end of a relationship -- yours and hers,” says marriage counselor Tina Tessina, Ph.D., author of Love Styles: How to Celebrate Your Differences.You should definitely keep mum if your concerns are self-serving, like you’re sad that you still haven’t found Mr. Right or you fear your friend’s marital status will affect your girl time. Things get even trickier when your concerns are more subjective. Marie, then 23, of Indianapolis, was surprised when her fiance’s family opposed the couple’s engagement. And she didn’t think they had any convincing arguments.“Subjective reasons like ‘too young’ or ‘too different’ are weak rationale when advising someone on a life-altering decision like marriage,” she says. Plus, you can't be sure if you're right. Marie and her hubby are celebrating their 16th wedding anniversary this year. On the other hand, don’t be afraid to speak up if you know something for a fact (not rumor!), like her fiance is a cheat or has a history of domestic abuse.If you really feel like you do have to object rather than forever holding your peace, these tips from Tessina can help:Think it through: Before sharing her misgivings with her recently-engaged niece, Denise, 46, first wrote down her concerns. “It helped to organize my feelings and opened my eyes to my personal biases,” she says. If that list is still screaming, "Say something!" the actual conversation should be face-to-face. “It’s too easy for sentiments to be misconstrued in emails or letters,” says Tessina.Lead off gently: Don’t launch into a diatribe about how the marriage is a huge mistake. Let your friend know that because you care so much about her happiness, you want her to know your concerns. “It’s best to have this conversation in a private setting and to avoid alcohol which intensifies emotions,” says Tessina.Know when to be quiet: Your friend will probably be hurt, surprised and defensive. When Laura, 41, expressed concerns about her friend’s speedy engagement, the conversation quickly escalated into a screaming match. “To this day, I wish I could take back some of the things I said.” Once you’ve stated your case and listened to your friend’s responses, drop it. “She’s an adult and able to make her own decisions,” says Tessina.Keep the lines of communication open: If your friend cuts off contact, send a note of apology or leave a message as soon as possible. “You should expect a bad reaction when you step on someone’s dream,” says Tessina. If she hasn’t come around in a week or so, try sending flowers and let her know that you’ll always be her friend. What comes next is up to her.Be supportive: Despite her reservations, Laura still participated in her friend’s wedding and wished the couple well. Even if you’re no longer on the guest list, Tessina suggests conveying your best wishes. “Your friend will hopefully see that a card saying ‘I'm so happy that you are happy’ means that you truly had her best interests at heart.” Whether the marriage lasts six months or 60 years, in the end, what matters most is that you are there if and when she needs you.