Хотя прошло уже больше 10 дней, он до сих пор не получил ее ответ на свое предложение.
"Even though more than 10 days have passed, so far he has not received her answer to his proposal."
slightly more natural, but less literal:
"Even though he made his proposal 10 days ago, he hasn't received her answer yet."
"Proposal" can be translated also as "offer", depending on context.
Other options: "more than 10 days have passed" -> "it's been more than 10 days"