but," she continued, holding out her two hands to Raoul, or rather giving them to him, as though she had suddenly resolved to make him a present of them, "but if we can not be married, we can ...

we can be engaged! Nobody will know but ourselves, Raoul.

There have been plenty of secret marriages: why not a secret engagement?
...

We are engaged, dear, for a month! In a month, you will go away, and I can be happy at the thought of that month all my life long!" She was enchanted with her inspiration.

Then she became serious again.
"This," she said, "IS A HAPPINESS THAT WILL HARM NO ONE." Raoul jumped at the idea.