We all arrived safely. 我们都安全到达。
Drive safely! (= Do not take any risks!) 谨慎驾驶！
Are the kids safely fastened into their car seats? 车里的孩子们都系好安全带了吗？
I think we can safely (= with no risk of being wrong) say they won't find us now. 我觉得我们可以有把握地说，他们现在找不到我们了。