If you want to meet adoptive mothers in Vietnam, you can consider the following methods:

1. Through social media: You can join through social media platforms such as Facebook, Twitter, etc. There are some groups or communities related to adoptive moms, interact with them and express your desire to meet adoptive moms. This approach may take some time and effort, but it allows you to connect with more people.

2. Attend events and parties: There are many social events and parties in Vietnam that you can attend to mingle with locals and meet foster moms. These activities can be volunteer activities, cultural exchange activities, music festivals, art exhibitions, etc.

3. Take a language learning class: If you want to better understand the local culture and lifestyle, you can take a Vietnamese language learning class. In the class, you can meet some local Vietnamese people, build friendships with them and learn about their lives.

4. Participate in volunteer activities: There are many activities in Vietnam that require volunteers. You can participate in these activities to contribute to the local community and meet some foster mothers. These activities can be volunteer activities in education, environmental protection, medical care, etc.

No matter which way you choose, you need to respect the local culture and habits, maintain an open and friendly attitude, and interact with the locals as much as possible.