I was fostered when I was younger and when I was older I sat on a fostering and adoption panel which approved foster carers.
When I was fostered I was a mess, I couldn't work out why my parents didn't love me and how anyone would ever love me if my parents couldn't even manage it. My foster carers looked after me but lacked when it came to listening and understanding. My foster dad told me to get over it as it happens to lots of people and happened to him. It didn't really help as its not easy to get on with your life living with strangers knowing no one cares. I would agree that it will be challenging, from my perspective I would say you need to be caring, understanding and able to just listen. Thats all I needed, I didn't need solutions I just needed someone to be there. It will take time for a child to settle with you, they have been taken away from their family and plonked in a home where they don't know anyone. Despite all the love you want to show them they may not be receptive at first but persevere and you will forever have someone who is so grateful (for the rest of their life) that one person was there and didn't turn their back. Good luck