Question: Is there an AI assistant that can help me write a heartfelt wedding speech or vow?

CelebrateAlly is a good option. The AI-powered service offers customized ideas for lots of special occasions, including weddings. It offers tools to write wedding speeches and vows, love letters and even plan romantic dates. The service is easy to use, taking only a few minutes to fill out a questionnaire to get customized plans. It offers more than 30 free products without requiring you to log in or enter credit card information, so it doesn't have to worry about privacy. Premium options are available for more features.

Another option is Verble. Verble is geared specifically to help you write speeches for various occasions, including wedding speeches. It uses a simple chat interface to ask you questions, then generates a draft that's clear and well-organized. With a smart editing mode trained on famous speakers, you can fine tune your speech. Verble also has a Practise Center for practicing your speech with webcam practice to help you with delivery. You can try Verble for free and upgrade to the full version for $9.99.