Singapore , Malaysia - have travelled their just as females - personal experience - its safe. Do research about every place you are planning to go. That way you can avoid any hassles like open-close time, holidays, also safer timings, what places to avoid in the night, etc. Read a lot of reviews in tripadvisor, they are super handy. I have planned whole trips based on that n it had gone smoothly.
Yes as @ashneys suggested Singapore Malaysia is safe for gals only trip. Or you can go through some travels like Thomas cook , make my trip where they will arrange everything.
