Deciding on a dress

Something along the lines of, "This is the dress that I've decided to choose for my wedding! I love everything about it, including the color. I'm going to begin the process of ordering it so it is here in time for my wedding."

If she replies with something negative about the color, you could dismiss it by saying, "Thank you for the feedback! I love the color, so I'm going to order it."

If you think she will try to withhold money to prevent you from buying the dress, a compromise may be to ask if she'd be willing to chip in for the veil (if you decide to buy one) instead of the dress.

if you don't want bright white you can always go with Ivory,

You don’t want her paying for it, so decline her offer fully. No pay, no say. She sounds very controlling, I’d keep details to a minimum with her if she’s proven she doesn’t have anything nice to say.

Honestly, if you two already don't have a good relationship, there are no magic words that will "...say that this is what [you] want without her getting mad about it." Instead I would go back to your first instinct about your dress and pay for it yourself. If she's not paying she gets no say. I understand that she will be upset, but that doesn't mean you've done anything wrong. Relieve yourself of the burden of trying to get her to see your side/like your choice. It's your choice and you deserve to make it with confidence.

Practice not volunteering any information about your wedding to her and changing the subject every time she brings it up. This will get easier, I promise!

Try, "I feel really beautiful in this dress. I see myself getting married to XX in this dress". If she still persists with her vision, it would be better to financially prepare to pay it yourself. BTW, all dresses will need alterations so budget for that as well. Common alterations are bustle, chest area or straps, and length. Best wishes.

I actually heard that pure white doesn't photograph well and it's better to go with an ivory or champagne. If you don't want to listen to her complain you could use that as an excuse.

Next time you go shopping and pull dresses that are not bright white, simply tell her that dresses without contrast do not photograph well, and you lose the details of the dress in pictures (and if you are paying that much for a dress, it better photograph well! ) Don’t hesitate to speak privately to your bridal consultant about the situation also- they are trained to handle difficult family members/friends. And sometimes moms tend to listen to the experts more than they do the bride, despite the fact she is the one that will be wearing the dress 🤦🏼‍♀️🤷🏼‍♀️ If you find “The One”, simply come out of the dressing room beaming from ear to ear and exclaim “This is it! This is the dress I am going to marry (insert fiancé‘s name) in!” Asserting that this is the dress you ARE getting really leaves no room for conversation or negotiation. And hopefully when she sees how happy you are in it, she won’t want to say anything negative.