Dear sir
In reviewing your project description, I’m submitting my proposal.
I’m Android/iPhone Senior Expert.
I am Mobile app honest developer that have a lot of experience in app developing for 7 years.
I can do it perfectly and I think this job is suitable to me.
If selected for the project, I would like to start immediately and devote my creative suggestions to your project in order to serve you better.
If you are really doubt on how fast I can complete, just give me a chance, I shall do my best.
I'm fully dedicated onto your project, can devote my full time to complete the job on time.
I can deliver high-quality result to you, fast turnaround time.
I would be happy to provide further information at interview.
I hope I have demonstrated to you my interest and motivation to get involved in your project.
Looking forward to your good reply.
Thank you for the opportunity to submit my proposal for your project.
Best regards.