Answer:
If someone says they are 'waiting' for a Mormon Missionary, that typically means that they plan on marrying them when they return home.
Here are some pointers on how to wait for a missionary:
1. Write them encouraging letters every week, avoid anything that might be too romantic or that would make them homesick, but be sure to let them know what is happening at home and that you support them. Be interested in what they are doing as well.
2. Send a package, if possible, every month or two.
3. Don't date other people, but be sure to surround yourself with good friends - you need social interaction!
4. Stay busy. Set a goal for where you want to be when he gets home, and focus on achieving it. Mine were related to my schooling and having a certain amount of money in savings.
5. The strength you can receive from staying close to God is vital! Read the scriptures, attend church, participate in institute, and attend the temple as often as possible. Make the mission a positive and spiritual experience for both of you.